Honda twin Engines: 1960-67 top to bottom

 Honda forums and my inboxes are full of questions about various aspects of these engines, so I will attempt to answer the bulk of them here.

                                                          Illustrations from AHMC manuals.

                                         Top cylinder head covers: Dreams, Super Hawk and Scrambler top covers are all different as to where the motor mounts bolt through. CL72s have solid mounting, but CL77s have a rubber insert to help lessen the vibration transmitted into the frame. 1960-61 engines with the rear crankcase breathers use a non-vented top cover and lack the breather plate, thus the bolt holes dimensions are different than later models.

Cylinder head castings for 250-305s are different in the combustion chambers are chamfer for the larger bore pistons. The fin pattern between the exhaust ports changed from a U-shape to a V-shape in 1965. Early engines have 10mm spark plugs (1960-61). CB/CL engines all use the same-sized valves.

CB tach drives are slightly different from 1961 to 1962 where the angle of the cable was modified.

Cam sprockets and camshafts have different spline patterns and the very early ones are massive flywheel-sized units. Cam sprockets for Dreams have different spark advance return weight sizes and springs than CB/CLs. From 1960-62, the locking nuts were RH thread, then switched to LH threads.

The camshafts, particularly the right side ones, were changed along with a dimension change to the point cam shoulder. There are a couple of different spline patterns on cams and cam sprockets, which do not interchange.

The rocker arms are all interchangeable, but there are two styles with different oil feed patterns. The intake and exhaust rocker pins have a different tip diameter so they do not interchange between the two types. Intakes have an 11.5mm OD and exhaust rocker pins are just 11 mm. DO NOT MIX THEM UP!

1961-62 cylinder blocks have 8 holes for studs and oiling, whereas the later ones have 9 holes, as the additional oil feed was introduced between the studs on the left cylinder. In 1966, the cylinders were die-cast vs sand cast and the tensioner pattern width was reduced from 41mm to 32mm widths across the mounting bolts.

Early crankshafts have slotted rod ends for oiling vs drilled holes for the later types. Later crankshafts have shallow splines, as do the transmission output shafts. Crankshafts vary between the 250 and 305 models due to the size of the balancing holes to offset the difference between the two different weight pistons. All Dreams have 360 degree firing crankshafts. The majority of CB/CLs have 180 degree firing, however there are Type 2 CB/CYP and some CL72 models with 360 crankshafts.

Speaking of pistons: Wow… first the CB72s had 10:1 compression, then 9.5:1, finally 8.5:1 in 1965.

CB77s had two versions: 9.5:1 and 8.5:1 in 1965. Dreams used two types of pistons, with the early 1960-62 versions having thicker rings. These were superseded to use of the thinner CB72-77 piston ring. There were some odd 4-ring pistons for early C72 models. Despite the difference between the crown shapes on CB and CA pistons, you can install CA pistons in CB/CL models with an increase in compression. The current aftermarket IMD piston kits for CB/CL models are modeled after the CA piston crowns. Expect to see compression readings in the 180+ psi range with these pistons.

Early transmissions have straight-cut gear engagement dogs vs back-cut types on later models. The transmission covers for CB models come in three versions: Early versions that wrap around the rear breather tower on the 1961-62 models. Then they were made rectangular;y with straight edges all around. The final model has a little cutaway on the left front edge which allows the engine vent tube to drop down into the transmission valley. Previously, the vent tube was routed along the back bone and dumped down towards the swing arm and front edge of the rear tire!

Interchange: Unless you have a domestic rotary gearbox transmission, all the shift selection parts are interchangeable between Dream, Super Hawks and Scramblers. Shift drums, shift forks, shift fork rollers and locking washers, plus the shift shafts (except for 1960-62 versions) will interchange. Kick-starter shafts and pawls are all the same for all models.

After 1962, all engines had primary chain tensioners and all of those tensioner parts are the same.

Engine cases are interchangeable, except the early 1960-62 rear breather cases and the ones without a primary chain tensioner mounting bosses.

Oil pumps are basically all the same, except the CL models which have an extended boss which fits between the frame spacers. You can use a CL pump on the CB/CA models.

Kick-starter covers changed locations of the clutch cable joints around 1965. While any kick starter cover will bolt up to any engine, the CB kick starter arms kick forward vs rear kicking for CA/CL models. CA/CL kick starter arms and knuckles are the same part.

The alternator stators are mostly interchangeable except the length of the harness leads are shorter on a Dream. Honda lessened the level of magnetism on rotors in 1965 so they are marked with a (L) after the model. All CB/Cls use CB72 marked rotors, while Dreams use C72 markings.

The clutches are a whole story all in their own. Early Dreams had a 4 plate clutch, then 5 plate. CBs had a 5 plate, then 6 plate then 5 plate again. CLs followed the CBs for the most part. Check your parts books for the correct usage. Use 22401-275-000 or 22401-323-003 clutch springs for all models. Dreams can use a 22401-425-003 spring. The preferred clutch assembly is for the 1966-67 CL77 and CB77 models. Note that early clutch baskets have solid-mounted sprockets, whereas the later ones have a rubber cush-drive sprocket. The rubber can shrink over time, so check the sprocket for a firm fit.

There are a number of inner clutch hubs which are machined to take the little retainer wires, but the clutch plate thickness are different as are the steel plates. The total stack height for any clutch pack is the same for all models. If you get it right, then the clutch adjuster index mark on the kickstarter cover will closely alight with the mark on the cover opening.

Carburetors had two different bowl shapes: Round and Square. The carburetors are interchangeable as long as the metering parts are the same. CB models have different needles and jetting than the CL models. 250 Dreams have smaller main jets than the 305 Dreams, but are otherwise the same part.

250-305 Dreams used either ND or Kokusan ignition points. They do NOT interchange. Most aftermarket versions of the Dream points are poorly made and don’t really work.

                                A few pointers from my Engine Repair manual....

NOT ENGINE RELATED: FYI

Ignition switches vary from year to year. CB models have 3 position switches, except for the CYP77 models which have 4 positions. CL models used a CB style ignition switch in the beginning, except the barrel of of the key switch is longer than the CB models. Then, they made a totally new switch which mounts to the frame with an adapter. Dreams and Benly models, for the US, are 5 position units, but Euro and JDM switch have a 6-position switch, which includes a stop for the little park light inside the headlight reflector.

9/2025 Bill Silver aka MrHonda

www.vintagehonda.com

www.mrhonda.guru

MrHonda is the X-man

 Well, this was round two for this 1967 CL77 Scrambler with a 68+thousand serial number. We don’t know what the last CL77 serial number was, but I seldom see them very high into the sixty-eight thousand numbers. Earlier this year, the bike was in for a slow-return idle problem that was caused by a missing camsprocket return spring. I did a sprocket-ectomy with the engine still in the chassis, which can only be done on a Scrambler. That went well, but the owner was complaining about the big jump to 2^nd gear and also some intermittent shifting problems. Plus, he wanted to do the X job on the transmission gears, so the 1-2 shift gap was closer together than it is in the stock configuration. I can’t think of any other transmission that allows you to do this kind of reset of the gear ratios. You get a closer 1-2 and 2-3 gear step, then a larger jump to top gear. For general street driving, this is a preferable update.

1st gear 2nd gear 3rd gear 4th gear

Stock

17.52 10.46 7.32 6.26

"X"d

17.52 11.70 8.26 6.26

Gears number 7 and 9 get swapped for  8 and 10.  Note #15 low gear bushing and #16 gear cotters.

I worked on the clutch when it belonged to the previous owner and I was the one who put the two gentlemen together to seal the deal and bring the bike down to San Diego from the previous location in Central California. The late model clutches are the best version to use on these engines, in that they have the cushioned clutch basket, the later 5-plate clutch pack and the outer pressure plate with the angled drain holes to help facilitate the expelling of excess oil trapped inside the clutch assembly.

One of my least favorite tasks is to R&R the engines out of Scrambler chassis for service work. With all the brackets and bolts and misc bits, it generally takes me about an hour to extract the engine and about the same to re-install one. I had the bike up on my bike repair rack to do all the removal steps, then lower it down so I can ease the 100 lb lump out of the frame and onto my little rolling cart. Fortunately, I have had an occasional helper who comes to learn about my work and he was strong enough to just grab it off the dolly and hoist up onto the work bench.

I had drained the oil previously, but more than a little gets trapped inside the bottom case which oozes out when you turn the engine upside down to remove the bottom case half. Starting with the two nuts on the top case, which hold the transmission cover bracket in place, the rest of the fasteners are all on the bottom. But to get to that point, you have to remove the clutch cover, oil filter, crankshaft locking washer and nut, then remove the clutch pack. The primary chain and front sprocket come off as a set and then you are down to removing the shift shaft and gear selection hardware. The primary tensioner and mounting hardware are then removed and you are ready to roll it back on its head, face-down to access the nuts and bolts that hold the cases together.

The engine had just over 10k miles and was in generally good condition internally. There was the usual layer of gunk on the bottom of the case as well as an 1/8” of collected crud inside the centrifugal filter. The gear dog engagement was minimal in the 1-2 gearshift steps and the shift forks had some scarring from being jammed into gear repeatedly. Pretty normal stuff, I find, these days.

The shift drum tracks were in good condition. I replaced the low gear bushing and reused the original kickstarter pawl/spring/cap. I have only a few remaining offset gear cotters, which are the “fix” for transmissions that jump out of gear due to a lack of gear dog engagement. I used 4 of the .020” first step cotters to move the engagement of the gear dogs closer together. Doing the X swap of the middle four gears also gives the corners of the gear dogs a better chance of a clean grab to the adjacent gear.

In the end, the gear dog engagement was probably 75% on both shafts, ensuring that the gears will stay engaged when selected. There is a certain amount of slack and float of the gears on the shafts, but this setup seemed to be a best-case scenario.

We had new reproduction low gear bushings made a year or so ago, which is always a requirement on most engines that need transmission repairs. Unfortunately, the offset gear cotters which were especially made by Honda to address the engagement problems were made from a hardened stamped steel and are not easily reproduced. I’m not sure what will become of all of the future engine and transmission repair jobs when the supply is permanently exhausted.

I replaced the shaft seals, cleaned the case halves and resealed the cases with MotoSeal. All the nuts and bolts were cleaned on the wire brush and installed where they belonged, torqued to specs. The oil pump was checked for flow and reinstalled on the bottom case. The engine doesn’t sit on the bench very well because of the cast-in boss on the bottom of the Scrambler oil pumps. I block it up with wooden blocks and reassemble the shift selection parts, the shift shaft, the primary chain tensioner and the whole clutch pack. The clutch cover gasket was a special extra thickness part from an eBay gasket company, called Emerald Gaskets, who is willing to make gaskets of over-OEM thickness material. So far, the gasket has held up okay after two removals. Leaking clutch cover gaskets are the biggest challenge to keep dry on these engines, so I am glad to find a product that works.

The engine was fitted with a Pro-Trigger electronic ignition system, which needed a bit of adjustment to get both sides to time up to the F marks. The carburetors were rechecked and float levels adjusted slightly to 22.5mm. The stock idle and main jets were kept in place. OEM needles, thankfully, were retained in earlier service work. The Keyster kit needles seem to be out of spec for these engines.

I was able to wrangle the engine down off the bench, stopping at the edges of the open drawers and then onto the little dolly cart. I wheeled it back to the waiting chassis and was able to lift it up about 6 inches to start it into the frame. I had already removed the left side exhaust studs which always seem to make thing difficult if left in place. Lifting and twisting, the engine finally found a home in the frame, but had sunk down below the engine mounting holes.

The bike was rolled back onto the work table and then a small floor jack again used to raise the engine just a little bit at a time, high enough to start some mounting bolts in place. The long bottom bolt and spacers have to be aligned just so, in order for the bolt to be inserted all the way across the frame, ducking into the oil pump boss and out the other side.

Once the engine mounting bolts are inserted and tightened down, the rest of the assembly continues, installing the carburetors, air filters and tubes, the exhaust system and stator wiring, etc.

1.5 liters of Honda GN4 10-40 oil was funneled down the oil dipstick tube and the footpegs installed as one of the last steps.

I had drained the gas tank in order to inspect the condition of the petcock. There was some leftover scale and deposits inside, so it was given an acid bath to dissolve the deposits and then flushed with clean water. Rolling the bike back off the rack, it was time for a start-up try. It came to life in a couple of kicks and sounded as normal as a CL77 can be. It still has the full weld-on muffler exhaust system, but they still have that distinctive Scrambler sound.

The customer lives here in San Diego and rode the bike in and then back home again. His bus pass gives him some other transportation options, rather than having to borrow a truck or trailer to bring the bike to me. His final wish was to have the tank and side covers re-painted Cloud Silver instead of the Candy Orange that was supplied at the factory. He rode the bike back home without incident and then hauled the bodywork off to my painter friend for a refinish.

This transmission repair took an easy 9 hours of labor, but it certainly was not “easy” work. I much prefer to work on Super Hawks and Dreams for engine repairs. But, this year has mostly brought CL77s to my garage, so you just have to do what you have to do…

Bill Silver

aka MrHonda

www.mrhonda.guru, www.vintagehonda.com

Unlikely Winner gets the win… Part 2

 Tearing down the engine to install the crankshaft gave a chance to look at all of the parts that I had lovingly fitted together the first time. All of the parts were looking pretty good, but the camshaft was working loose in the minuscule cam bearings of the early 1-piece head design. I consulted with my cam-grinding friend and we decided to have the cam journals turned down, hard chromed and finished back to size again. I was assuming that the wear was more on the camshaft than in the cylinder head. For the most part, this modification worked well, but an installation of needle bearings on both ends of the cam would have been even better. Wobbling camshafts cause erratic ignition timing because the point cam is on the end of the camshaft. Any play will change the point gap, which changes the ignition timing. I just had to keep an eye on the wear and tear during and after the races to see if the problem would worsen or not. Ultimately, I was able to race the whole season with that combination without failure.

I was so buoyed up after the first AFM race, that I joined the CMC (formerly the ACA) and thus had two or more chances to race each month. Other than a disastrous piston seizure at Orange County, when I forgot to re-jet the carb after I removed the air filter (I was riding the bike on the street between races!) the little orange bomb just ran and ran…. and won and won again! When the two Yamaha brothers showed up, running their 100cc bikes in the 125cc class, I showed them the door rather convincingly. One decided to join me in the ranks of the 4 strokes, and bought his own CB 125 Honda. He decided to have noted engine specialist Jerry Branch port the cylinder head to get an edge on me, but the valve springs collapsed through the enlarged intake port and he was back to square one again. Despite my home-built engine (I ported the cylinder head myself), he was never able to head me at any of the tracks.

All kinds of bikes made appearances during the year. I recall someone showing up on a Suzuki 125 Stinger, a Bultaco Streaker (very trick bike!), Sears 125 street bikes and one particular guy who kept showing up with a flyweight Kawasaki 90, that was getting faster every race. He always had problems when he got into each race, however… he generally crashed on the first lap. Either his over-enthusiasm and/or lack of brakes on the tiny converted, enduro machine caused him to crash on the first or second lap. I always figured that if we were ever to stay on the bike, I would probably be in trouble by the end of the race. He never did defeat me, but came close at the last race of the season, back at Riverside Raceway. Even in practice, I noted that he would pull slightly away from me on the back straight, as both of us exceeded 80 mph. By the middle of the race, we were passing and 15 re-passing each other, repeatedly, as my bike would out-brake him and out accelerate his peaky two-stroke in the slow corners, only to have him run me down on the straightaway. The harder he pushed the little Kawi, the more it developed a “speed wobble” going through Turn 9, at full throttle. I tucked in behind him, coming out of the turn, watching the machine shake its head more and more. Finally, I cut the corner sharper than usual to get out of his draft and watched him as he wrestled the bike at speed.

Just as I was moving past him, headed for the White Flag, I caught a wild motion in the corner of my eye and took a quick peek. Rather than back off, to settle the bike down, he persisted in trying to keep ahead and finally the machine had decided that that was enough and pitched him off at 80+mph. I finished my last lap in 1st again, which clinched my 125cc Production championship and watched nervously as the rescue crew attended to the fallen rider and machine. After the race, I went to check on him and assisted his father in getting the battered Kawasaki into his truck. I heard, a week later, that the rider had suffered multiple fractures of one ankle. It took over a year to rehabilitate his injured foot and leg. A couple of years later, I received a wedding invitation from him and I decided showed up to relive the moment again as well as to bid him a happy married life. He never raced again, after the crash, but did build and maintain a race bike for a friend. I had not had any crashes for the entire season, luckily, but my turn was coming up a few years later.

Honda CB125 Production Racer in a nutshell:

Starting with a brand new, stock machine, I replaced the rear 17” rim with an 18” hoop and installed a set of Yokohama Road race tires in the 2.50x18” sizes. I added a set of S&W shocks on the back and replaced the handlebars with some clubman bars, routing the excess front brake cable so it continued to function correctly. Off came the turn signals, passenger pegs, side stand, centerstand and any other excess chassis items, not related to racing. In its final form, the engine had these modifications: CB100 head (no chamfer on the combustion chamber = higher compression) lightened valves, S& W valve springs, Yoshimura Road Race camshaft, point cam, slipper skirt piston (The XL125 had a similar piston crown configuration), lightened crankshaft (MUCH smoother at 11k rpm!). Cranking compression was 225 psi! I found that the carburetor from the XL125 was 24mm vs the stock 22mm mixer, so installed one, with some improvement in top speeds. I discovered that there were different transmission ratios for the various CB/CL/SL100-125 versions, so installed 2nd and 3rd gear sets from a CL100, I think. I used the stock ignition coil and points, but added an additional spring leaf to increase the pressure on the points at high speed. On some occasions, I removed the rotor after I had checked the ignition timing prior to the race.

The muffler was stock in the beginning. I ground off the edge welds once and split the muffler open, removing the baffles and added some length to the exhaust pipe, but the weld broke the first time we raced it, after we had welded it back up and re-chromed it again. I had to grind it apart again and remove the loose pipe extension. We just welded it back up, almost empty inside. I added a little accessory fiberglass racing seat to save some weight and lower my riding position. CB125s came with solid foot pegs, so we cut them off and welded on some fold-up pegs, in the same location. The rules at that time for Production Racing were that it had to have a stock frame, gas tank, muffler, front forks and that the engine must use parts that were offered in that series of machines (no 32mm carburetors from a 350cc machine, for instance!). You could overbore to .040” and you had to use the stock crankshaft stroke length. Engine modifications for four strokes included pistons, camshafts, valves, racing transmissions (same number of speeds as the street version, though).

The Honda was pretty happy with the 5-speed gearbox, due to the torque of the engine, pulling out of corners. 1973-74 was when the RD125 Yamahas started to appear and once they were ported for power, the low-end torque was gone. It was necessary to “slip the clutch” in slow corners for the Yamaha riders who were carrying those TA125 racing transmissions in their crankcases. One particular machine, ridden by a lady officer of the racing club, was my constant nemesis and I never did defeat her and her heavily-modified RD125. The other bike that only showed up a couple of times was John Ulrich‟s “Killer Deek” 125 DKW Enduro machine. When it was first brought out, it was on par with my bike, but once he had some Sachs engine guru massage it, there was no contest. The bike came with a 6-speed transmission, 30-32mm carburetor and went about 90 mph. Despite the “leading link” front fork suspension, the combination of John‟s riding and the horsepower of the bike overwhelmed to everything else in the class, winning the championship easily in 1975. Because of the number of races I attended and mostly won (including my win at a “one-time” event at Laguna Seca), I scored sufficient points in the class to be the 1974 125cc Production Champion in both the AFM and CMC racing clubs.

I was quite thrilled to have accomplished this feat, using a new $549 street bike, $600 worth of racing parts, a pair of hand me-down leathers and USAF service boots to put a 4-stroke Honda single in the winner‟s circle. For me, my first year of road racing was exciting, rewarding, challenging, scary and weary. Being owner, builder, financier, transporter and racer was more than I had ever done before and the end result was success. I attended the awards dinner in No. California to receive my championship trophy, surprising the group by making the 500-mile trip just for dinner and a cup! It was a pretty wild group and I was glad to have a designated driver, my cousin Suzy, who lived nearby, in my corner.

                                               The results of the 1974 125cc Production class wins.

Tow Vehicles: I had a number of different cars during the year, all of which had to serve as a transportation vehicle for the little Honda. I bought some sturdy bumper mounted racks, designed for motorcycles and strapped them onto an early-70s Toyota Corolla station wagon and a 1949 Cadillac 2-dr fastback, at varying times of the year.

Over the years of moving and getting married, the stash of trophies were all disposed of, but I kept one plaque and my award for being the 125cc Production Championship. It’s been 51 years since my first year of road-racing adventures and most of the people and details have faded away, but I have to say that my uncharted efforts, just to see what it was like, left me with a bit of pride in knowing that you can often achieve your goals if you just keep trying, despite the challenges and obstacles on the path. I saw the potential in the little bike and learned a lot about engine building, tuning and riding at various tracks that are mostly all gone now.

I won races at Carlsbad, Orange County, Riverside, Ontario, Willow Springs and even at Laguna Seca racetracks and only two of those venues are left, now in 2025. I hadn’t planned on continuing to race after the 1974 season, but once the racing bug bites you, it is hard to go back to your pre-racing life, even at this low level. I upgraded the racing experience to 350-400F bikes for a few years, but eventually tragedy struck one of my 6 hr endurance race teammates and in the following year, 1980, I had a BIG get-off that ended my racing efforts completely.

I think everyone has had moments of triumph and a sense of accomplishment in some area of life that should be recognized and held onto deep in your soul as a moment of glory and self-worth. It doesn’t have to be a Championship effort, recognized by your peers and family. Only you know when you have done the right thing and felt the sense of accomplishment and achievement. Carry that memory forward, towards more experiences like that which make life worth living.

Thanks for indulging me, reading my story of the past. I appreciate your feedback and comments. No one really remembers those moments, other than me. Sometimes little snippets come to me in my dreams at night and when I awaken the little voice inside my mind says “Share your story now”! If you are sitting on your own success story, then share it now, before it is too late.

Bill Silver

aka MrHonda

www.vintagehonda.com

Unlikely Winner gets the win… Part 1

 About 10 years ago, I sat down to transcribe my history with the Honda motorcycle brand, beginning in 1967 with my first motorcycle, a CL90 Honda Scrambler. Walking through a period of some 50 years of riding, buying/selling and experiencing a wide range of vintage Honda motorcycles, I wound up with some 60 pages of my personal involvement with the Honda brand. This story is an excerpt from the bigger “In search of a Honda” story, a Hondabiography, if you will.

From the beginning, it took me 7 years to enter the realm of sports racing and it ended with a good result in the end of my year of efforts. Starting with an unlikely base in a 4-stroke Honda CB125S1 125cc street bike, I was able to modify it to a point where it was competitive with a good many other branded 125cc models which were available during the early 1970s. I really only entered the fray to see if I could make the bike fast enough to keep up with the current crop of similar street machines and learn something about riding competitively, although on the bottom rungs of the racing scene. I didn’t go into it with hopes, dreams and the drive to become a winning rider, it all just sort of happened on its own.

My little piece of motorcycle racing history culminated in winning the 125cc Production Class Championship running in two different racing organizations that year, the AFM and CMC. I began my road-racing hobby in 1973 on a $300 CB100, with one win at Willow Springs, when only two bikes were entered and I was the winner at my first racing experience.

                                                        AHMC factory photo CB125S1

1974

With amazing synchronicity, Honda released an upgraded version of their formerly drum-braked CB125S in 1974, installing a trick cable-operated disc brake on the front wheel. I felt that this combination would be just the answer to fulfill my road-racing dreams. Then, I discovered that Yoshimura Racing was selling Road Race pistons, lightweight crankshafts and camshafts for these bikes! I started with the slipper skirt racing piston and camshaft, along with some racing valve springs. When I installed the camshaft in the head and turned it on its bearings, I discovered that the valves would hit each other on the way back to overlap. Pops Yoshimura had his own unique ideas about camshaft ramp opening and closing profiles, which were extreme to say the least. I didn‟t know why they designed this cam the way it was, but I decided to grind down the edges of the valves, until they had some clearance when they opened. After that, I had to slot the cam sprocket and degree in the camshaft, so the valves wouldn‟t hit the piston. Eventually, it all came together and I fired it up and ran down the street, with the tachometer barely able to keep up with the newly revitalized engine. I tried to break in the piston and rings as much as I could without running the motor up to red-line in each gear, but it was quite difficult. I changed the jetting a bit, still using the stock carburetor and found it really “perky,” as well as “peaky” for a little four-stroke single. These bikes peaked at about 65 mph in stock condition, but it was now pulling past 75 mph and might have even more in it, once it got on the track. I felt that I was ready to take on that swarm of 125cc two-stroke (mostly) Production bikes, as the season opener at Riverside Raceway loomed near. Everything was brand new to me, including the track.

To go racing, you have to have the correct safety gear from head to foot. I didn’t know where to go find a road racing set of leathers, but I knew a guy…

The Floyd Emde family lived in National City and Floyd had his motorcycle shop on National Ave. Floyd and his son Don, were the only father-son winners of the Daytona 200 race in history. I guess that I asked Don about where to find some used racing leathers and he said, "Oh, I have some spare leathers from when I was racing with BSA." We happened to be the same general size and for something like $50 I had a set of real racing leathers. My USAF boots and gloves were sturdy enough for the task and I purchased a Bell Star helmet to finish off the gear list. It was time to go racing!

I rechecked the “fixed” ignition timing (Yoshimura racing points cam) and headed out for some practice laps to determine if the jetting and gearing were going to be correct for the track that day. Riverside Raceway was WAY different than riding in the mountains or even at Willow Springs. Turn 9 was a banked sweeper where you could just keep it wide open and lean over as far as you could. At the other end of the track, Turns 6 and 7-7A were a series of snaky S-bends, up and down hills requiring off camber braking in a corner. It was kind of disconcerting at first, but with only 125ccs underneath, it wasn’t likely to buck me off from massive applications of power in the turns. I did plug checks to check the main jet sizes and rechecked everything a few more times in the second practice session. The bike was pulling towards 80 mph, but vibrated like CRAZY at red-line (11,000+ rpm), numbing my hands in just a few laps.

I entered both the 125cc GP and the 125cc Production classes, in order to get some track time and dial in the bike. The GP race was, of course, a flop for me, as the winners were going about 90-100 mph. Back in the pits, a fellow racer came by to tell me that my lap times were good enough to have placed me well into the Top 5, based on last year‟s race times for the Production class. That was pretty terrific news to start the day! I nervously eyed the competition in the Production race, noting a gathering of older Yamaha 2-stroke twins, a Kawasaki 90, and other street-based machinery. I think that there were about 8-12 entries in the class and I was the only Honda four-stroke machine to be seen. They waved the flag and off I went, slipping the clutch at 10,000 rpm and paddling along with my feet to get some forward motion built up before the first corner.

First lap, first corner racing is pretty intense, as everyone is vying for the lead simultaneously. The little Honda pulled out towards the front and everyone found their own pathway through Turn 1 and concentrated towards the next section of the track. As I accelerated through the turn exits and used the great disc brake to setup my corners, I found a good rhythm after a lap or so, in the thick of traffic and began to pull towards the front-runners. I tucked into the “draft” of all the bikes ahead, wherever I could and finally pulled out in front, by a slim margin. Of course, my competitors were using my speed to keep me close, as well, looking for an opening to pass or slingshot by me on the straights. I kept my head down and watched my lines through the corners carefully, lap after lap. I was relieved to see the White Flag, signifying that we were on the final circuit and when the Start-Finish line appeared again, I was alone in front! New bike, new track, new everything and I won my first 125cc Production road-race! Pretty thrilling stuff for me and even my fellow racers were surprised at the speed of the CB125. I was a happy guy, but my hands were again numbed by the engine vibration, so I decided to invest in a racing crankshaft for the little “Racer that could.”

                                                            Racing at Carlsbad Raceway

Casa del Honda is a busy place….

 Now that my broken thumb is mostly on the mend, I have been taking in some repair work a little at a time.

This month, two CL77s were in, plus the little CB200T was sold. Now a new challenge has arrived in the form of another SL90 (check old stories for the first oddball version) and as well as a restored CB92 with subtle carb problems. Oh, then there is the sad, but promising 1965 CB77 project recently acquired.

First, the little CB200T with the broken camshaft found a new home in Oceanside, CA about 70 miles away and circumstances created me having to deliver it for a $100 fee. Between replacing the camshaft and the starter switch, and a new front rim/tire. The bike mostly sat in the garage due to the hand injury.

Once the 200T was out of the way, one of my clients who had purchased a 1967 CL77 from an earlier client, brought it back as the spark timing wasn’t returning properly. It would require a cam sprocket replacement, which can be done with the engine still in the chassis, but it isn’t an easy task, The ultimate reason for replacement was that the spark advance return spring was missing! It took several hours to complete the task, but now the engine idle problems are solved. Now, the customer wants the transmission gears X’d and that will be a full engine pull, bottom end tear-down and replacement of the usual parts, including the low gear bushing, no doubt. That one is on HOLD for now.

The next CL77 project came back to me, as the customer reminded me that I had rebuilt the engine when I lived in San Clemente, back in the 1996-2001 era! For some reason, I installed a S12 337cc kit, which now gives 200psi compression readings. The bike was being prepped for sale, and has been mostly revived and repainted. It even still has the old Probe electronic ignition system in place, but needed a full carb cleaning, petcock cleaning, and overall tuning and service work. I couldn’t even pull the clutch lever in due to heavy clutch springs that Honda had specified in later years. Those got tossed and replaced with normal springs, used in CB77s, then the clutch adjuster was replaced with one of the new CMSNL reproduction units. Now I can pull the clutch lever in normally.

                                                             AHMC factory photo-CL77

Then, the rogue CB77 that was offered to me back when I had a broken hand and was recovering from the Hawk GT650 crash. The bike was abandoned with a friend of a friend of a friend, but did have a clean CA title on non-op status. It had been sitting outdoors, about a mile from the ocean for a couple of years, and was covered in rust and corrosion. With a healed hand, I chased down the players involved and was able to pick it up when I was already in N. County for a chiropractor appointment, which is 40 miles from home.

                                                               AHMC factory photo-CB77

There is a separate story on the CB77, which at least did turn over and gave the impression that it had been operated in the last few years. I serviced the carbs, recharged the supplied battery and the bike actually fired up and sounded pretty healthy. The over-sized tires were replaced and some fenders acquired to replace the missing ones. The “cafe” handlebars are being replaced with OEM style flat bars and lots of de-rusting will be in the work flow. UPDATE: Sold to an enthusiast in AZ.

Update on the latest SL90 engine project: It took about 3 hours to full disassemble this relatively simple engine. The whole engine was covered in scale and rust to start with and there were non-standard copper washers under the cylinder head nuts. The point cover screws were rusted in place, so needed the use of an impact driver just to access the point plate, which was also corroded. The camshaft had a non-standard looking set of lobes and the valve springs appeared to be some kind of heavy duty racing parts.

Once the cylinder head was removed a GIANT high-dome piston was revealed inside the cylinder. The piston had a groove cutaway on the side to allow for clearance on the spark plug tip. Once the cylinder was removed, it was apparent that this was the biggest 90 piston allowed at 55mm. The bottom of the cylinder wall was 1mm thick. The piston had no signs of actually being used or run in as there was no trace of carbon on the crown. The engine had been sitting with the piston at near TDC, so some rust had formed below it on the bottom of the liner. When engines sit outdoors, untouched for years at a time, whatever oil that was on any parts above the oil level runs off exposing raw steel to the atmosphere inside the crankcases. With changes to temperatures and weather conditions, the air space condenses moisture into water droplets which attach to the exposed steel parts and the rust process develops.

With the top end removed, I attempted to remove the clutch cover screws, using my tried and true vintage impact driver, using various sized hammers. Basically, none of them would budge in spite of repeated blows. The only way to remove them was to use a chisel and notch the edges of the screws, then work on the edges with the chisel and hammer with repeated blows. Slowly, each one finally gave up their grip on the case threads and finally backed out for removal. It took 1 to 2 minutes per screw to remove the clutch cover, only to discover that the asbestos cover gasket was coated with sealant. So obviously someone had been in there previously. In fact, the little cover over the end of the clutch release plate only had one screw instead of two and the screw type was incorrect.

The shift drum detent plate screw was glued in place as well, requiring more demolition work for extraction. Every inside screw needed the same hammer and chisel effort for removal. With the cases split there were rust spots on the outer edges of the crankshaft, near the connecting rod. Only the transmission gears had escaped the rust attacks.

At this point, several options are under consideration. First, just find a decent used engine and start over again, using the old engine cases. Second, replace the monster piston with probably a 12:1 compression rating down to a normal S90 piston and cylinder. The camshaft profile may or may not work as an upgrade to the stock cam. In any case, I have more than 3 hours of pretty intense labor just disassembling this engine and am left with a pile of rusty and corroded parts to show for it.

BTW the carburetor and manifold which had water damage inside the bowl, still had the stock jetting, which never would have worked on the engine combination that was assembled. The cylinder head did show some signs of port work, but it is apparent that the project never reached fruition.

Fortunately, I went onto a S90/CL90/SL90 Facebook forum and saw some engines for sale in Louisana. That lead to a conversation with the owner who is closing out his collection of bikes and parts, including a nice CL90 engine and a whole SL90 engine. He’s willing to ship them to SoCal once we determine which option is the best. It does take a village to get some of these old bikes back into service once again.

AHMC factory photo-SL90

UPDATE:

I received a mostly intact CL90 engine from my friend in LA, nicely boxed in a reinforced plastic container. After I extracted it from the mound of peanut packing, the disassembly began. To my surprise, the top end contained a recently re-bored to .25mm piston and cylinder, all in great shape. The disassembly of the cases followed the same path as the first one. All the case screws were seized up in their threads and required repeated blows from a big hammer and chisel to break the thread bonds loose for removal. There are 9 screws in the center cases and it took several minutes per screw to extract each one.

Once the case screws were removed, the case halves were separated carefully and the transmission gears and crankshaft were extracted. Overall, the transmission gears were in fine condition. Again, because of sitting somewhere moist for many years the outside of the shift forks had a fine layer of rust buildup. A combination of rust removal and a wire brush cleaned them up for re-use. The inner cheeks of the crankshaft were also freckled with surface rust and were also cleaned with similar results.

Starting with the newly vapor blasted engine cases, I removed the existing transmission bearings which had been contaminated with vapor blast media and swapped them with the CL90 bearings. A new seal was installed in the left case half and reassembly of the transmission and shift fork unit was performed. The crankshaft was installed in the left case and a new gasket laid down. Gently the cases were reassembled but the kickstarter gear engagement with the transmission caused some difficulty, until the engagement was completed by turning the kickstarter shaft slightly and pushing the cases back together again. I had a set of leftover new case screws available from the last engine build, so was able to snug the cases together.

The next step was to disassemble the cylinder head and clean the valves. Another trip to the vapor blast shop had it looking fresh again, along with the cylinder which was stripped of the original black paint. The cylinder was taped up for a fresh coat of paint. The cleaned up valves, which showed nice seating patterns were reinstalled. On the 90 engine the intake valve was fitted with a small valve stem seal. The head was reassembled and then the rest of the engine began the assembly process.

The engine cases go together but with some tricky business to get the kickstarter shaft and gears to nest into each other so the cases will fit up properly. All the transmission gears were in good shape. The camchain tensioner roller needed to be replaced, but the rest of it slowly found its way back together again.

The SL90 carburetor is pretty unique and all the carb kits that were offered were of the S/CL90 style float valve which is not used on the SL90 engine. After some research, I found that the carb kits for the XL/SL70 used the same float valve, so that finally solved the problem. The float bowl was plastered with JB Weld and after being vapor blasted, a hole was found in the bottom of the bowl. More JB-Weld was employed to help seal it all up again.

You have to remember to install the camsprocket on the chain before you put the cylinder head back on the motor. It’s all a little puzzle of parts that go back together in a specific sequence. I discovered that the rubber packing gasket B came in two types with the aftermarket kit. When I had filled the engine with oil, a leak was discovered coming out of the camchain chamber and around this gasket. The chamber area is not a rectangular shape, but bows out on the outside. I wound up using the piece that was in the engine previously that had the correct shape to prevent any oil leaks.

Fortunately, the replacement cylinder and piston were ready to install after a bit of cleaning. It’s hard to find shops that will do boring of small displacement engines here in San Diego, so we saved time and money with the Louisana CL90 motor. Tearing two of these motors down to make one takes a good bit of time and effort, but it is looking good for installation now.

Bill Silver aka MrHonda www.vintagehonda.com

PS

I’m finding that those green “non-asbestos” gaskets from Thailand and elsewhere are seeping oil out of the gasket material. Am I the only one that has noticed this problem?

The 1973 CB350 has an Un-Fourtunate twist

 A referral from another customer, dating back a few years, lead the owner’s of a 25k mile CB350F to my door, owing to poor performance issues. Initial compression readings were in the 120 psi range, except for #3 cylinder which measured 80 psi! The bike was picked up from a local auction company and was in somewhat sad original condition. After purchase, the bike was disassembled and the chassis powdercoated. A tapered steering head bearing kit was installed and lots of work was done to brighten up the engine surfaces. The oil pan was leaking, the valve cover was leaking and the oil pump was leaking oil, and those issues were remedied before it came to me

Day 1

The first thing I did was to remove the spark plug cap and measure the resistance value. Typically, you want spark plug caps to read out less than 5k ohms. This one measured 11.5k ohms. High resistance spark plug caps are a leading cause of poor performance due to weak spark at the plugs. So, first thing on the list was a set of plug caps. Carb kits were installed, but apparently only the float valves and jets were replaced. My experience that in these days, stock #75 main jets are a bit too lean, especially when using today’s E10 alcohol gasoline. In the past I have installed #78 or #80 main jets with good results.

After the owner’s departed, I proceeded to remove the air box and the carburetor rack, plus the coil set from the frame. I was warned that the #4 cylinder spark plug threads were damaged and was shown a spark plug that had rounded off threads, but just way at the end in the first few threads. I have a thread chaser tool to help clean up the threads, so spent some time in working it down into the head to attempt to clean up the threads. The hole was pretty badly damaged, so may need an insert installed. The bike was dropped off around 7pm, so I concluded my work for the evening, but was noticing that the valve clearances seemed to be very tight, so the next step is to check and adjust the valves, then do another compression test, followed by a leakdown test to see where the low cylinder pressure is being lost.

Day 2

The compression readings went up to 150/150/150/120. The head was determined to be a write-off, so another one was purchased from an eBay seller. It supposedly had only 14k miles on it, but there was a considerable amount of carbon build-up on the back sides of the valves. Valves were all removed, cleaned and new stem seals added. The combustion chambers were somewhat carboned-up, so they were all cleaned out with a rotary wire brush. Once everything looked good, the head was reinstalled onto the cylinders with new gaskets and seals. After torquing the head down, the rocker arm cover was installed, valves adjusted and new spark plugs installed.

The carb “cleaning” was apparently from some months ago, so even though the engine fired up on full choke, it wouldn’t run off-idle properly. Off came the carbs again and this time all the idle jets were checked and all found to be plugged up. Not only that, the emulsion tubes were all plugged up with old fuel deposits, so the fueling was completely out of whack.With #78 jets installed and the emulstion tubes and idle jets cleaned out, the carbs began to work normally. I spent over 6 hours in one day, cleaning and installing all the bits and pieces.

Day 3

The bike came in with some older Ram-Flow 2into2 mufflers, which were trashed. The owner’s had rounded up a set of “new” OEM 333 code 4nto4 mufflers, but reported having difficulties with the #3 muffler which was twisted about 10 degrees from vertical and was about a 1/4” off at the inter-connectors that balance the exhaust chambers together. In addition when the two mufflers were installed on the bracket, the header pipe flanges were not parallel to each other.

Installing each muffler in the cylinder head highlighted the fact that the #3 muffler was incorrectly welded onto the header pipe at the factory. Carefully cutting the weld away from the header pipe and muffler, allowed the muffler to align up with the #4 pipe connection and mount up up the rear braket properly. The system was installed again, so that the header pipe could be marked for a re-weld.

I hauled the muffler down to a local automobile muffler shop who had reworked my Jaguar XK8 mufflers about 5 years ago. I was able to hold it just right for long enough to get a tack weld done. I rechecked the marks and gave him the green light to weld it all up again. The muffler was remounted on the bracket and everything lined up as originally designed.

The customer came by with the repainted fuel tank, which was installed and fuel turned onto the carbs. The bike fires up quickly and sounds like a 350 Four should sound with the original mufflers installed. There was, of course, more difficulties with the tank. First, there were remnants of rust and corrosion left inside and secondly the petcock lever required two hands to move from one position to the other.

After the tank was drained so the petcock could be serviced, it was noted that the 4-hole gasket was kind of out of index. The gasket was new, but something was causing excessive drag. The lever face was cleaned up and reassembled, but the problem remained. In the third round of inspection, a second wave washer came loose from the other! Apparently, the old gasket was leaking, so the additional washer was added in an attempt to seal the leak! Removal of the second washer resolved the petcock lever issue, at last.

The bike got a quick test ride locally, as it doesn’t have any license plate. It pulled up to redline in third gear and was running happily now. These bikes were never particularly fast, but are relatively comfortable as a beginner bike with a smooth motor.

Bill Silver

aka MrHonda

www.vintagehonda.com

Dream Carb Dilemma Solved...

From many posts I see on the various forums, many concern the correct carburetor adjustments and settings on the CA77 305 Dream model.

                                    

Both the 250cc and 305 models use the same 22mm carburetor body with just different jets. The main settings for the common CA77 are a #35 idle jet and #120 main jet. Float level setting is 26.5mm for both models.

What seems to be occurring is that the carb kits from the Keyster company are coming in with #40 idle jets and #130 main jets, along with a poor copy of the slide needle. OEM needles will have a K#### number stamped just below the last needle clip groove.

K22402 is the needle for the 250 Dream carburetor. 16151-259-004 is the 250 needle part number

K22401 is the needle for the 305 Dream carburetor 16151-266-004 is the 305 needle part number.

The dimensions of the float valve and needle from the Keyster kits often differ from the OEM parts. The needle length and depth of the float valve seat can vary as well, causing problems with properly setting the float level.

Recently, I was trying to assist a Dream forum member who was having problems with fuel-fouling the spark plugs in just minutes. I ran the whole set of specs by him and offered other possible solutions, but the problem didn’t go away with any of his repair attempts. I happened to have what was basically an unused CA77 carburetor that came with a batch of other loose 250-305 parts. I offered it to him for sale and he eagerly made the purchase. A few days later, with both carbs in his hand, he began to compare parts and specifications. His old carb had a #40 idle jet installed, which was obviously a kit part. In comparing his old jets with the ones from the new OEM carb he determined that using some guitar strings to clean out the idle jets, the #40 in his carb would allow a .027” wire to pass through the hole.

The Keihin jets are metric-sized, so a #35 idle jet is .35mm or about .013”. So his #40 stamped idle jet was actually about a #70 size instead. Bingo! In all of his work and worry about why his bike was running so rich and kept fouling plugs, it was an over-sized pilot jet as the main culprit.

As I guided him through the carb inspection and settings process, he asked if the float valve needle was supposed to be compressed when the float level gauge was used to determine the correct height. That was incorrect! As shown in the Honda shop manual drawings and descriptions, the float height is determined by allowing the float tang to just rest on the spring-loaded tip of the float valve needle NOT compressing it. Compressing the needle will give an inaccurate float level setting and cause performance issues.

                                                        Factory Shop manual illustration

He sent photos comparing the OEM and the Keyster kit float needles and they are markedly different in size and shape. I have found that the needle seat depths are different than the OEM parts and in some cases the whole height of the float valve seat is different than the stock parts. These vital part dimensions often lead to having the floats banging up against the roof of the float chamber when the float height is set with these inaccurately sized parts.

Factory Shop manual illustration

The kit needles are often incorrectly made. My friend, Ed Moore, said that the Keyster carb needles for the CB77 kits actually work well on CL77 carb applications. When used on CB77 engines, they tend to run rich,, causing plug fouling or just poor part throttle performance. Unfortunately, there are few remaining companies that provide carb kits for 60 year old Honda motorcycles, however, the ones being produced have had the same problems for the last 20 years. I have had to use a paper punch to notch the float bowl gaskets on the square bowl carburetors because the material was stamped too wide and the gaskets flip up against the two guide posts on the front straight side of the carburetor bodies.

In cases where air filters have been changed to a different type or just left off completely, the fuel metering will be insufficient, so an increase will need to be made on the main jet. The same can be said for a change in the exhaust system where aftermarket mufflers are used in place of the OEM originals. At times, the needle clip position will have to be changed in order to smooth out the transition period from idle to mid-throttle positions. You have to test ride and make determinations about what the engine actually wants, once you have deviated from OEM intake and exhaust systems. Raising the choke slowly when the engine is struggling will be a helpful indicator to determine that the engine is running lean at part throttle.

When you are tuning up any of the 250-305 engines, knowing the stock specs and settings is crucial as a starting point for further adjustments. For Dreams, it is #35/#120 jet combo that is the starting point. Of course, erratic ignition timing and air leaks at the flange and insulators can cause upsets with the stock settings.

07/25

Bill Silver aka MrHonda

www.vintagehonda.com

1975 CB200T-roubles X2

Just when things quieted down, just a bit, a new rescue opportunity presented itself online…

They always look better in the pictures, but this low-mileage Orange CB200T had suffered a catastrophic failure, which I had never seen or heard of before. I found the post, somewhat by accident on OfferUP classifieds, and it was located in Pacific Beach area, about 25 miles from me. The post showed about 8 photos, including the one where the end of the camshaft had broken away from the camshaft body. In person, the bike was suffering from the usual 50-year-old chrome pitting and alloy corrosion, not to mention that it was just pretty dirty from sitting somewhere exposed for a good part of its life.

One can only imagine what would cause such an unusual failure of such a sturdy Honda part. I couldn’t even guess at the cause, unless someone had tried to over-tighten the spark advancer bolt on the end of the camshaft and somehow broke it off in the effort.

The owner, Corey, had purchased the bike for basically market prices for a running, titled and registered 1975 Honda street bike. When I went to have a look and purchase it, he said that he was riding it back from a fresh purchase and somewhere along the return ride, it just went Bang! And that was the end of that. He admitted that he wasn’t much of a mechanic, but tried to figure out some possibilities on his own, including replacing the ignition coil, which was valid as the plug wire was broken at the coil case and attempted a few more things, until he checked the points and found the end of the cam was broken off.

We loaded it up into the Tacoma and off I went on a new, puzzling adventure with a little CB200T, which was the final successor to the line of 160-175 from the mid-1960s to the early 1970s. Honda had reworked the engine with larger wrist pin sizes for the pistons and rods, plus created some rubber intake manifolds to reduce some of the shaking and quaking of a 200cc engine with a 360-degree firing crankshaft design.

I offloaded the bike in the driveway and started peeling parts off of the chassis. I was quite surprised to find that not only did the footpegs have thick rubbers, but the whole footpeg and sidestand assembly was rubber-cushioned where it bolted to the frame. The engine’s OEM carbs were disassembled in a box and a pair of shiny new Chinese copy carbs tucked into their places. The Chinese versions of replacement carbs only goes so far, as they chose to put two right-side carburetors together as a set, instead of replacing the normal left and right oriented carburetor configurations. Using two right side carbs puts the left side carb adjustment screws inboard between the pair, as well as causing the left side fuel hose to exit on the left and then snake around to meet up with the petcock on the right side of the fuel tank.

I proceeded to remove the side covers, air box covers, air filters, which are fitted with the rubber connector tubes to the carburetors, all in one piece. One of the pluses of the bike was that it still had intact OEM mufflers that hadn’t rotted out on the bottom. Soon, it was time to yank the hefty motor out of the frame and put up on my Work-Mate bench to drain the oil and remove the top end for further inspection.

I have a handy 18v power ratchet which helps buzzing off a lot of long bolts and makes the tasks much quicker. The top cover came off easily, as long as you remember the little 10mm bolt in the front edge. Then, I had to puzzle out how to get the camshaft out of the head. One of the apparent changes from the 175 to the 200 engine was that the 200 now had an endless camchain and a bolt-on cam sprocket, instead of the earlier bikes with a master-link type camchain and pressed-on sprocket. The camshaft is bolted to a removable sprocket with 2 bolts, then you have to pull the rocker arms and shafts, giving clearance around the camshaft area. I dismounted the chain from the cam sprocket after removing the two bolts. Then, it was a matter of snaking the camshaft out of the head and camchain. I tried moving the chain to one side of the camshaft mounting ears and then the other, but it seemed like the cam was a bit too long to just tip it out of the head. The end of the camshaft that is part of the tach drive has a thin, hollow knock pin that connects the tach drive end with the camshaft. Removing the knock pin allowed the camshaft to finally be worked loose from the head.

Next, the cylinder head was lifted off and taken to the workbench. Looking at the colors of the carbon on the valve heads looked like it didn’t have a lot of miles on them, backing up the 5300 miles showing on the speedometer’s odometer. Another change to the 200 engine is the use of long-reach D8EA spark plugs vs the older D8HA plugs with about a 1/2” reach. I used a special tool to clean up the spark plug hole threads, as one side looked a little bit like it had been cross-threaded at some point.

The piston crowns were carboned up, and the ring identifying marks were worn off. When I turned the engine over to allow the pistons to go to the bottom of the stroke, I could see recent honing marks on the cylinder walls that were not factory-made. Lifting the cylinders off revealed the green gasket material used on aftermarket D&K gasket kits from Thailand, so obviously someone had been poking around inside the engine in recent times. The repair history was unknown to Corey, but there was a sticker on the tail light lens that had the name of a shop in SD County. One might infer that whoever had the top end apart and back together again might have failed to tighen up the spark advancer bolt sufficiently and with a few miles driven, the whole thing went sideways in a big way.

Some previous owners had replaced the stock CB77-sized tires (2.75x18 front and 3.00x18 rear) with a 3.00 x 18 front and a 3.50 x18 rear set of IRC tires. Not only that, but the rear shocks were all shiny new and apparently just about a 1/2” longer than the OEM shock lengths. This caused the swing arm to be pushed downwards towards the mufflers, basically preventing chain maintenance or wheel removal without dropping the exhaust pipes down. In one of those odd MrHonda synchronous events in my life, someone had dropped a bunch of misc used parts with me a few years ago. The only part that I thought would never be used was a pair of OEM CB200T rear shocks! I found them, disassembled them for cleaning and reassembled them to use as a replacement for the too-long aftermarket shocks on the bike now.

I popped the wrist pin clips out of the pistons so I could clean off the carbon build-up and remove the rings to check for excessive end gaps in the cylinder bores. For some reason, Honda uses two, seemingly identical piston rings for the top two positions. On most all of Honda’s piston rings, the numbers are marked on the top with a T or oversized mark, but the “scraper” ring only has a 2 mark, as I recall, for placement of the ring in the second piston ring land slot. Unlike most other scraper rings, which have a very decided scraper lip on the bottom edge of the ring, the rings for 175-200s have these mystery rings instead.

So, I ordered a bunch of replacement parts for the little bike, including all new cables, a new battery, new spoke kit, a new front rim (rusted badly), engine gasket kit, while still fishing for a good used camshaft to get this bike back on the road again. Honda made the 200T bikes for 4 years, so you would think that parts might be floating around. There is some use of 200T engines parts for the AHRMA racer group, so I might hit them up. Ironically, right after this bike was posted on OfferUp, another horrible ratty parts bike showed up for $250 asking, which might solve the camshaft problem, but then you wind up with a pile of ratty used parts that no one wants.

Thankfully, a member of one of the two CB200T Facebook groups replied to my pleas and actually turned up a nice, used camshaft with the advancer and sprocket still attached for $60 plus shipping.

More problems arose when I dismantled the front mechanical brake caliper to allow for a cable change. There is a little cone-shaped spring that puts pressure on the plastic disc that helps the brake to be self-adjusting. Of course, the spring was not to be found so the only one listed for sale on eBay was in Thailand.

Someone had listed a front brake cable on eBay, but it looked like a conventional adjustable brake cable seen on most drum-braked vintage Hondas. It was listed as fitting a CB125 and CB200T, plus the CL200 models. Obviously, the two different brakes require different cables and the one arrived as the CL200 version. It was only about $12, anyway, but the seller refunded the money and I kept the cable. Finding the correct cable is kind of difficult and I found a seller in Norway who had one for $40 with free shipping! According to the eBay listing, the seller had sold 155 of them already.

There was a big ugly spot of rust on the front rim, so I found a NOS rim at CMSNL and some spoke kits from Thailand. The next search was to find a 2.75x18 front tire so I could change out the whole rim, spokes and tire at the same time, the use that tire to install on the back wheel to get the tire sizes correct once again.

I had the top end components, including the cylinders, cylinder head, end covers, tappet covers and top cover vapor-blasted by my local friend Jon, who has the whole setup in his busy garage. I’ll scrub up the bottom end as much as possible and the rest will go back together with a shiny top end and patina on the bottom.

The rear fender chrome was pitted in the section beneath the seat, so it was removed and cleaned up. The front fork seals were on the list of repairs, so those were purchased. The intricate boots are NLA, apparently but are not torn at the moment. It is easier to rework the front end when no engine is installed.

Fork seals were replaced and the engine started up successfully. I drove it around the block and down a half mile away from the house. It seemed to be running well, but the petcock, an aftermarket version, was leaking internally. I had to drain the tank and disassemble the petcock to find out what was going on. The back side of the fuel lever was somewhat distorted and running a smooth file across the face revealed the high spots and low spots.

It was all going well, until I checked the headlight bulb, which tested fine. That only left the infamous starter button switch, which was a problem for a number of the mid-1970s models. The handlebar switch also carries the brake cable, brake lever and front brake light switch. I bought a switch from Indonesia that was supposed to be the replacement for the OEM switch but the internal switch function was poorly designed and blew the main fuse out when it was tried. Shockenly, the few new OEM handlbar switches were listed at between $250-300 and all were in Asia somewhere.

After consulting the wiring diagram and looking at the Instant ON headlight function, I decided to rewire the starter solenoid so it used the handlebar switch to ground the circuit, instead of toggling the 12v to the starter solenoid. Using a readily available CB175 switch seemed to be the answer. It won’t have the kill switch function, but will have the option of turning the headlights On/Off manually.

(See the accompanying story about the headlight switch fix)

In the middle of all the repairs and parts ordering, I crashed my 91 NT650 Honda Hawk GT650 and broke my thumb, so doing repair work is challenging to say the least now.

June UPDATE:

The bike engine was repaired, the front rim was replaced with a NOS one and a new tire installed.

The aftermarket petcock kept leaking internally, so a NOS OEM Honda petcock was purchased for about $60. The registration ran out at the end of April, so I titled the bike in my name on PNO status.

I was torn as to whether to keep it around for a local parts chaser bike to sell it as my garage was otherwise full of 305 Super Hawks. I put it up for sale.

In the last few weeks, another CB200T showed up as a customer bike, which had been dead for about 10 years. Pulling the carbs apart for cleaning and inspection revealed that the carb slides had been installed backwards, which caused fuel fouling of the spark plugs and stalling at an idle.

The petcock was incorrect with one fitting instead of two for the carburetors. I replaced it with an aftermarket unit that was correct for the bike. There were LOTS of issues with electrical system components, as all the turn signals and the headlight were converted to LED lights. The handlebars were changed to a lower version and all of the switch wiring had been routed outside of the handlebars instead of through the insides. The fork ears were replaced by aftermarket units which had slid down the fork tubes, which had been painted. The paint cause grounding problems for all of the wires inside the headlight shell. The wiring harness was an aftermarket piece, so sorting out the correct wire colors became an issue.

The mechanical front brake caliper was frozen up inside, so the brake was non-functional. It was disassembled for cleaning and lubrication while a new OEM brake cable was ordered and installed in the same process.

The engine was tuned up with camchain adjustment, valve clearances checked, carbs cleaned and ignition timing reset. The spark advancer was removed and cleaned/lubricated, as well.

With aftermarket handlebars, the cable lengths were a bit off and needed to be routed differently.

The “cafe” look had been accomplished by cutting up an original fuel tank and creating a bump-stop seat! The stock tank had been sealed, but the gas cap was coated with the tank sealer, so a new fuel cap was ordered and replaced. Ultimately, it all came together and was picked up after being in the shop for a couple of weeks. My broken thumb is getting stronger and I can do a lot of mechanical work again, but the hand is still a little weak and sometimes painful.

Anyway, as so often happens to me, not one but TWO unusual bikes showed up during the same month, and they are now back on their wheels and in circulation once again.

Bill Silver aka MrHonda

www.vintagehonda.com