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