Dreaming in California; 1963 CA77 305 Dream (Pt. 2)

The engine build went along pretty well, as planned, but there were issues to solve that required some creativity to some degree. Starting with the bottom end, the transmission did receive a set of offset cotters to help improve gear dog engagement. The low gear bushing was refreshed, as well. Once the cases were bolted back up, the unit was flipped back over for top end and clutch side assembly. I discovered that you could stick a 3/8” drive extension with a medium sized socket on the end and poke the whole thing through a connecting rod to keep the engine from turning over while tightening up the big crankshaft nut. Using a ½” drive ratchet and extension on the 4 prong special tool gives a nice snug tightening experience without the usual hammering with a dull chisel on the nut flats.

The engine had 15k miles, according to the speedometer, so the primary chain was somewhat slack, of course. Once the clutch plates were all cleaned and sorted, the primary side was all assembled with no major traumas. The shift shaft did turn out to be one of the “short” ones, but the splines are good enough to reuse the shaft once again. The oil filter was actually fairly clean, so someone had serviced it at least once in its life; perhaps when the top end was rebuilt.

The oil filter drive chain was REALLY loose and sloppy when the filter was fitted up in the crankcase hole. These little chains are hard to find as they are a few of those “universal” parts used on ALL 250-305 wet-sump twins. None of my usual resources had a spare chain available, but research revealed that the chain is a fairly common #25 chain pitch. The factory chain is endless, but these small chains can be purchased with a master link, allowing for building a custom chain for this application.  An eBay seller offered a 3’ long chain with master link for less than $14 delivered. The chains are used on those little pocket bikes, so they should be sturdy enough to just spin a little oil filter round and round, I hope.

When the original chain was measured with digital calipers, the length was about 18mm. The new chain showed an overall inside length of 16.5mm and when fitted to the engine resulted in a very nice fitting chain with minimal slack. I am in contact with a company in the UK who apparently has these chains in the correct endless lengths as well as a potential replacement primary chain, which is another hard to find part now.

The cylinders were honed and looked mostly good except for an area of staining about mid-travel down the bore. New rings showed nice end gaps, so the piston/ring package should be good to go this time. The endless chain is somewhat easier to wrangle during engine assembly, once it has been looped over the camchain guide roller. Those rollers are NLA from Honda, but were beautifully reproduced by CMSNL in Holland.

The original cylinder head had a large section of broken fins, so the hunt was on for a correct “U” shaped fin replacement. A check on eBay showed a decent looking head up for auction of the correct type and miraculously it was located right here in San Diego. It turned out to be perfect for my needs and at $60 a bargain, as it included valves and springs. The fins were all perfect and combustion chambers/spark plug holes all in great shape.  Honda Dreams had their own exhaust valves until CA77E-1025681, when Honda just installed regular CB72 (268 code) exhaust valves in the rest of the production run. Both of these heads were early version (the front fin shape cutaway is U shaped, instead of V shaped), so all of the valves were the same. The best four valves were cleaned and installed, although the intake valves had a little step in the valve face angle, they seemed to seal up after a little lapping work.

The cams were like the rest of the internals… all varnished up, but not scored, worn excessively or damaged. Even the camsprocket was in decent shape, so was reused after the return springs were checked for nice return action on the weights. The cam bearings were all replaced from stock on hand. The rocker arms and shafts were all installed and the cams lightly started into each end of the head. While it is possible to slip the camsprocket in and under the camchain with the head in place, it is probably easier to insert the camsprocket into the chain before dropping the cylinder head down onto the cylinders.

Care must be taken to ensure that the pistons are both at TDC, before the camsprocket is positioned into the camchain. To hold the whole top end down in place, a couple of short 3/8” sockets were slipped over the exposed stud ends and secured with some 8mm nuts. This helps to clamp the gaskets down in place and gives just enough slack to allow the cams to be installed into the camsprocket, which was positioned with the 0 mark at 12 o’clock and the flats parallel with the cylinder top cover surface. The left side cam (right side as viewed during assembly) is tapped into the awaiting camsprocket’s master spline first. I did install both of the inner cam bearings into the head first, with the outer bearings pushed onto the camshaft shoulders for insertion. Once the camshaft catches the sprocket’s splines, it will hold the camsprocket in place while the piston position and cam timing landmarks are all rechecked one last time. When the proper cam timing is verified, the right side camshaft, with the point cam mark pointed upwards can be gently tapped into place. After the cam has engaged the splines, attention must be made to ensure that the point cam’s shaft tang end engages the inner plate of the spark advancer unit. On a 360 degree firing engine, the point cam has double lobes, 180 degrees apart, so you can get away with installing the point cam shaft in “backwards” and not suffer any timing issues. You cannot get away with this on a 180 degree firing engine, however. If you make that mistake on a CB/CL 180 degree motor, then you would have to install the points plate in upside down in order to get the engine to run. That makes for a very untidy installation, so do it right the first time.

Once the camshafts are installed, the end covers have to be placed over the ends of the camshafts where the edges push the cam bearings deeper inside the cylinder head openings. I usually install each cover without the gaskets at first and secure each cover with 2 screws, mounted diagonally to hold them in place. At this point the camsprocket position can be checked to see if it is in alignment with the bottom chain sprocket on the crankshaft. You can sight down the chain and see if it is pulling to one side or the other. Small adjustments can be made by tapping the camsprocket slightly to one side or the other until the camchain run looks to be straight.

Once this is achieved, you can snug down the camshaft nut tightly. I have an adjustable hook wrench which works perfectly for this function, but the old “dull chisel” or a wide flat-bladed screwdriver can be used as a tool as long as the handle is strong enough to endure some hammering on the end. Remember, that in most cases, the camshaft nut is a left-handed thread! Once the nut is secured, you can remove the end covers, tighten down the left cam’s through-bolt and then install the gaskets correctly and tighten all 4 screws on each end.

All that is left is to install the top cover gasket, breather plate (drain holes for forward/down) one more gasket and then the top cylinder head cover. Torque the cap nuts to 15-16 ft lbs. and you are ready to install the camchain tensioner on the back of the cylinders and adjust the camchain tension. This engine still had the “early” style camchain tensioner, which has the tensioner bolt on the left side.

There is more work to do on the right side; of course, installing the rotor with fresh starter roller springs positioned inside the starter clutch hub outer, which should be tightly screwed to the back side of the rotor. The starter chain, if showing excessive slack, can be shimmed by using thin washers beneath the starter motor mounting points. Otherwise, the chain is the same pitch as the camchain, so a replacement can be made from a spare camchain and master link. OEM starter chains are endless, but using a replacement with a master link is perfectly acceptable. Remember that this chain only turns when the starter motor is activated; otherwise it just sits quietly in place when the engine is running.

Tim McDowell http://www.classichondarestoration.com/index.php has quite a few replacement parts on his website, so an aftermarket air filter and tube were ordered from him, along with new chromed cap nuts for the head and an engine screw kit.

Dreaming in California; 1963 CA77 305 Dream (Pt. 3)

Back to the chassis work…

Starting from the back, the brake shoes for the rear wheel were down to about 1.6mm, which is to be expected for a 15k miles bike. New shoes (4mm) were tracked down from David Silver Spares in the UK. He has a warehouse in PA, so parts can be ordered here in the US and shipped inexpensively from the East Coast. The brake drums needed to be scrubbed as a thin layer of rust had coated the braking surfaces over the past 17 years. A new rear sprocket was purchased from Nick at Ohio Cycle, who had the 29t 525 pitch sprockets re-manufactured. David Silver Spares also came up with correct early-style rear wheel dampers. First generation dampers have little hooks to secure them to the hub, whereas the later ones had pull-through nipples which inserted into holes drilled in the hub center.

The shocks were dismantled and NOS chrome lower covers installed ($95 each). Pitted, rusty shock covers really stand out on a Dream, so the decision was made to go bucks-up and replace them. I wound up with four extra lower covers from other spare shocks, which have been sent to the chrome-platers for revival. The tail light mount was cleaned of excess powdercoating to ensure proper grounding for the tail light assembly. The tail light mount on this bike was welded to the rear fender at the factory.

The bike came with a tire pump, but the pump was missing. The brackets and lock were still present, but there was no key for the pump lock. I tracked down some key blanks, which work on some of the tire pump locks, but this one was number 311 and the blank didn’t fit easily. A local key shop ground down the bottom edge of the key enough to allow the blank to fit into the lock assembly. Without even being cut to the lock code, the blank will release the lock from the bracket.

The ignition switch had an odd blank hand-cut to fit the lockset when the bike was received. The lock code was easily detected and a NOS OEM pre-cut key was purchased from an eBay seller. The key and lock were matching numbers, but the key wouldn’t fit all the way into the lock! Some spray lubes were shot into the lock to help loosen things up, but the key continued to resist full insertion. I couldn’t quite see where the conflict was on the key, so I tapped the key deeper into the lock with a hammer and slowly it went deeper into the lock. Finally, it went in deep enough to engage the tumblers and the lock worked in all positions. The key still was hanging up when it was removed and reinserted, but it was working after a fashion. I had a reliable eBay key supplier cut a T-series blank to the code and when it arrived, it fit in and worked perfectly. Holding the two keys side-by-side, it is difficult to see the difference between the two, but one works a lot better than the other one.

The handlebars looked similar to OEM Dream bars, but closer inspection revealed that they lacked the little alignment punch marks used on OEM bars and the wiring holes were round instead of oval shaped. A new starter switch/throttle housing came with the bike, but the throttle drum wouldn’t fit over the end of the rechromed handlebars! The end of the bars seemed to be a little out-of-round, so finally I put them in a vise and squeezed them a little at a time until the throttle drum slid over the end correctly.

The dimmer switch was the original part, so was cleaned and reinstalled. The lever brackets were installed ahead of the switches and the original, small-ball end levers were straightened back over a block of wood, using a plastic mallet. These early bikes used clamp-on CE71 mirror brackets and mirrors, so the lever brackets do not have mirror mounting holes. These brackets were also used on early CB92s and are difficult to source now.

David Silver Spares also came up with a NOS headlight rim and at first claimed to have a set of the special fork bolts which retain the upper shock mounts to the fork. Ultimately, they could not source them in Europe, so some $25 replacements were found and purchased. The bike had been assembled with standard bolts in place of the correct stove-bolt style fork bolts, which looked out of place in that location.

Clauss Studios supplied a Gray fender packing and chain guard inspection hole plug. These parts were changed to Black later in the production run (CA77-314731-on). Once the engine is in the chassis, the front wheel/fender can be more easily removed for fitting of the fork bolts and the fender packing.

Stay tuned for Part 4... engine in the frame and fired up for the first time in over 16 years.

Dreaming in California; 1963 CA77 305 Dream (Pt. 1)

It has been a quite couple of weeks, here in Spring Valley, as we lead up to Christmas and the holiday season in general. With the last few bikes down the road and with new owners, only the C110 remains for sale.

Last week a long-time local friend sent a message to me with photos of his partially reworked CA77 for sale. He’s had it for over 20 years, tore it down after purchase then powdercoated the chassis, along with rebuilding the wheels. A small bag of NOS Honda parts had an included parts invoice dating back to the year 2000. Some chrome work had been done and a bit of polish work finished on the kickstarter cover and a few other small parts. The speedometer showed 15k miles and had a rather tatty-looking face and odometer numbers. The engine was stored at another shop, so I await its arrival along with whatever other parts are stored in boxes scattered around the premises.

The frame number is 310129, so the 129^th CA77 built for the 1963 production run. The wiring harness tag still showed 1962, which isn’t surprising considering the low production date. The bike still had one “Dream 300” tank badge, one of the two tire pump brackets (the side with the lock) and a new set of handlebars.

There are numerous differences among the “early” (1960-63) Dreams and the “late” (late 1963-67) versions. Early 250cc Dreams were distinctively different, especially concerning the fuel tank shapes and designs, even between the 250 and the 305s of the same years. Late Dreams were more generic and shared all the same chassis parts equally. Another bonus feature on the early series models was use of stainless steel for the mufflers! Again, even the mufflers changed configurations with the first types using a sleeve-type muffler inlet gasket while the later ones used a captive o-ring seal up front.

Other nuances concerned the use of gray rubber for the front fender packing and the chain inspection plug. Early bikes used clamp-on mirror brackets because the lever brackets were smooth on top with no provisions for screwing in an 8mm mirror. The original levers are more delicately shaped with small tapered ends and miniscule ball tips to finish the shape.

The horn connectors from the wiring harness had little hooks on the ends, which were secured with tiny cross-head screws to the horn body connections. The throttle control is a single, screwed-in twist throttle cable connection. Missing from the early Dreams is the little HONDA logo emblem, located just below the headlight assembly. Many early Dreams used a Yazaki brand speedometer and there was a mix of Nippon Denso and Kokusan electrical system components. Pre-65 Dreams generally had a “round bowl” carburetor configuration vs. the later “square bowl” design.

Until about 1966, all Dreams used a tall, thin battery (MJ-2) which required a matching tool tray, ground strap, side cover (and knob), all of which were replaced/redesigned when the 12N9-3A Super Hawk battery was introduced. The frames, of course, had a modified battery holder, so they all had new part numbers which reflected those changes.

The “base” product code for a C72 is 259 and 266 for the C77s. Numerous worldwide product variations added more product code numbers. Many of the basic Dream chassis components are rooted in the original 250 code dry-sump chassis, dating back to 1957. So, don’t be surprised if you are parts hunting and discover codes ranging from 250 to 272 for whatever application you are working on. Remember that US bikes were never equipped with “winkers” (turn signals), but all had dual seat lengths. Models sold outside America usually did have winkers and often had solo seats and luggage racks for more versatility.

HNY to all (updates)

Well, the engine arrived just before Christmas and it was a pretty scary sight to behold. The seller mentioned that it had been “stored in a chicken coop” for the past 15 years and it looked every bit the part of that. Curiously, the engine DID turn over with a wrench on the end of the crankshaft bolt. That was pretty amazing to discover, given the poor storage conditions.

Engine teardown went pretty routinely all things considered. Always start with loosening all the external screws with an impact driver, while the engine is still in one solid unit. Once the screws are loosened, then the top cover nuts come off to access the cam chain master link. Once the link is parted and the two nuts removed next to the spark plugs, the head slips right up and off the engine. With some persuasion, the cylinders rocked loose and lifted off the pistons. Close inspection of the rings indicated that the pistons/ring set were .75mm oversize, so someone had been inside this one once before. 

Basically, everything was kind of varnished and gooey, but nothing really bad was discovered deep inside the cases. The clutch, of course, had fused into a single mass, but it peeled apart, one plate at a time with the steel plates looking like they would clean up with a wire wheel session. As far as could be determined, the cases had not been split before as the sealant was nice and neatly applied all factory-like. I always check to see if there is sealer in between the two right side shafts (kickstarter and output shaft). Often there is no sign of sealer there, which has contributed to mysterious oil leaks on these early series engines.

Once apart, the major components were taken to a local automotive engine rebuilding shop, which shares a steam cabinet with a transmission repair shop. Generally the parts are cleaned of oil by this process and I get a call back in a day or so. Three days later, I called and was told that the parts were just getting done at that moment because the rotary function of the steam cabinet had failed, so the final cleaning was being done by hand.

After that the engine parts were hauled up the road, some fifty miles to a shop which had recently acquired a vapor blast cabinet. The parts have to be degreased before they go to this step, so having come out of the engine shop for de-greasing, they were ready for the final cleaning step. Even with this technology, getting the grit and scale off of these 53 year old parts is a chore and numerous hours were expended in the cleaning process. In the end, they were bright and shiny. Pitting and etching of the metal is to be expected considering the storage conditions before retrieval but the overall surface finish is clean and shiny.

The cylinders will get a good hone job and pistons refitted with new .75 rings which have a nice end gap in the cylinder bores, so no need for a rebore and new pistons/rings this time. This is a savings of something like $250-300 in machine work and parts acquisitions, so we caught a little break there, however the cleaning charges pretty much cost the same in the end.

The only real anomaly for the engine was that a set of the “flat” 268 coded tappet covers were all in place, instead of the usual “domed” 259 code parts. Many of the 1960-62 engines that have been in the shop have had the 250 code dry-sump Dream tappet covers. The flat 268 covers, for the most part, came out in 1961 with the release of the CB72-77 models, although most of the 1961 engines seen over the past 4 years still had carryover 250 code Dream tappet covers in place, as did an early 1962 CL72 that was here last year. The flat 268 code covers were superseded back to the domed 259 code parts, according to Honda’s parts interchange history book, but flat covers were seen on many CL72-77 models throughout production until the odd, half-dome 1967 tappet covers appeared with no specific part number attached.

Another transitional oddity has been observed at the tail light assembly. While the 1962 model Dreams came out with the tiny rectangular tail lights originally, most of the US bikes had the tail lights either updated or later ones equipped with the “short” 268 code tail light lenses through the end of the 1962 production, it appears. That "short" lens has been seen on 1962 CL72s, C110s and CB72-77s just for that year. Because of the lack of depth on the lens dimension, the tail light bulb socket was tilted up about 45 degrees from horizontal. Normal “long” lens lights have a bulb socket that extends straight out, horizontal with the ground. This early 1963 CA77 seems to have the original light socket still on the bike and it has an angled bulb socket, indicating that it was probably built with a “short” lens tail light assembly.

Part of the clues for this is that the tail light wiring consists of two very thin wires, which extend all the way forward to the wiring harness connectors without any mid-point connectors. Most long lens tail lights have a couple of wiring connectors just past the back of the bulb socket. A separate set of wires comes back from the harness to connect to the tail light wiring. The Dream wiring consists of two thin black wires with color codes just back of the connector ends. A CB77 tail light would be joined by a pair of wires, which were white (tail light) and blue (brake light) for their full length. So, if a lens is available, the bike will be equipped with a 1962 style short tail light lens, which appears to have been the original factory supplied part.

Back to the engine rebuild; this one will be assembled with an endless camchain, which is about all that is left for sale these days. There are sellers who will supply an endless chain, plus a rivet-type master link, but you will need a staking tool to complete the job that way. The 250-305 engines can be built with an endless chain, contrary to popular belief. The trick is to keep the cams spaced apart when the cylinder head goes on, then with the camsprocket held up by hand; the camshafts are carefully driven into the sprocket’s splined ends. Usually you have to use some short sockets over the ends of the cylinder studs and held in place with some 8mm nuts, simulating a torqued down cylinder head. This shortens the overall stack height and allows the camchain to stretch up sufficiently to allow the sprocket to engage with the camshaft splines. It is kind of a tricky move, but I have done it several times with complete success.

O-ring confusion for 250-305 Honda twins

Super Hawk and Scrambler twin carburetor models

While the port sizes on the twin-carb heads are basically the same for either a 250cc or 305cc engine, the Bakelite insulators have different markings and ID holes. The 250cc bikes received 22mm carburetors and the 305s are fueled by 26mm mixers. The 29mm o-rings with part number 16173-260-004 should be used on both the carburetor flanges and the matching insulators for the 305cc carb installations. 29.0 X 2.4 16075-GHB-B70 and/or 91304-KPH-700 are other part numbers with similarly-sized o-rings for 305 twin carb applications.

The 250cc Super Hawks and Scramblers can use the 91302-PF0-003 O-RING (26.9X2.4) parts on both the carburetor flanges and the insulators. Unfortunately, many Honda parts listings are showing the 91302-PF0-003 O-RING (26.9X2.4) as appropriate for the 305s, when they are actually sized only for the 250cc 22mm carburetors used on CB/CL72 models. Many Honda part numbers have been superseded to something newer that “almost fits” with some effort and in a few cases the “interchange” attempt has gone wrong and often unnoticed except for people like me and a few others! Check current online Honda microfiche listings for CB77/CL77 cylinder head and you will probably see the PFO O-rings listed there instead of the 260 code parts. They won’t work!

CB72 listings show O-RING (27X2.4) 16173-253-004 for the carburetor. Cylinder head listings show O-RING (26.9X2.4) 91302-PF0-003 (replaces 91301-253-000), but that 91301-253-000 O-ring is shown as 28.5mm.

Dreams (single carb models)
On the CA77 images for the cylinder head, we see: 

O-RING (26.9X2.4) 91302-PF0-003 (replaces 28.5mm 91301-253-000 ?) 

For the carburetor section the listings show O-RING (24X2.4) 16173-250-004 (replaces 16173-202-004. (FYI a -202- code part is for a CA95 Benly with a 20mm inlet size). The problem being that the Dream carburetor inlet is 22mm size, but the carburetor flanges have a 32mm groove in it, so these do not fit.

O-ring options from Honda for the Dream carburetor flanges are now:

31.7 x 2.4 91307-958-003

32.5 x 2.4 91356-ME4-003 

32.5 x 2.5 91307-MC8-005

When working with “almost the right size” o-rings, you can often get them to seat into the grooves well enough for assembly and effective sealing. Ones on the small size can usually be stretched into place. If they are a bit on the large size, a little squeezing down can be tolerated within the groove space. There are some SAE near equivalents at www.zoro.com and www.grainger.com if all else fails, but measure carefully, as some offerings are listed by OD (outside diameter) and others are ID (inside diameter). 

MrHonda’s “not for profit” CL90 sale completed…

It’s funny how just about anything that you put up for sale (vehicle-wise) puts up a fuss and fails to cooperate when it is given the opportunity to move onto greener pastures. 

After countless hours of building/rebuilding just about the entire derelict CL90 chassis, which was married to a S90 gas tank and half of the engine, the bike failed to start up on the night before it was to be picked up.

This funky bike’s story continues on with the buyer contacting me from a Craigslist posting, showing interest in it, but he lived 500 miles away in San Jose. Just last week, I was able to secure a PNO title only for the bike after repeated inspections. Once the pending title was secured from DMV, the buyer stated that he was coming down to San Diego and would pick up the bike with his rental car; in this case a new Toyota Highlander! After some “negotiations” for an even greater discount of the $995 asking price, (including boxes of spare parts), he did show up early on Veteran’s Day morning ready to test ride it before concluding the sale.

Almost as an after-thought I decided to check ride the bike once more, only to discover the “non-starting” gremlin had returned. The bike had run beautifully after jetting was worked out, with easy starting and a nice steady idle. Suddenly, we are back to square one with no spark to the plug. In the process of troubleshooting the problem, I used a screwdriver to flash across the open points in order to complete the ignition circuit. It worked randomly, acting somewhat like a failed condenser. Prying the points apart with the screwdriver tip I sensed that something was amiss with the ignition points. 

Moving them open with the screwdriver revealed a sense of sticking on the contact arm.

This ignition plate was the original S90 part which was once submerged with water, leaving a high-water mark on the inside of the points cover and across the point plate. The plate was disassembled and soaked in a rust neutralizer solution to help recover the surface condition. The points were left in place during the process and the refreshed point plate reinstalled into the cylinder head opening. For the most part the ignition worked okay, but randomly it would lose spark and there was no clear clue as to what/why this was happening. Once the point plate was removed from the cylinder head, the point arm could be more easily moved on the pivot pin and it was apparent that this was the problem for the point’s motion failure. With the points removed from the plate, the tiny screw hardware for the point wire was removed and the point arm gingerly pulled off the pivot pin. There were signs of corrosion inside the point arm sleeve bushing and certainly greenish corrosion on the pivot pin, as well.

The pivot hole was cleaned with a quick pass of a drill bit, while the pivot was scrubbed up and lubricated. When the two components were reunited, the pivot action of the point arm was greatly improved. The point plate was all reassembled and placed back onto the cylinder head cavity. The point plate had been marked as to where it was located in the head to set the initial timing, but when the engine was kick-started there was no immediate response apart from a very loud backfire BANG! The dyno cover was removed to allow access to the rotor markings and the engine turned over with a 14m wrench. Suddenly the ignition timing was about 40 degrees late and the points were barely opening at all. Apparently the clean-up pass with the drill bit overdid the arm’s original ID and now the points were somewhat loose on the pin and the point gap was nearly zero.

The engine was turned over until the point cam was at the highest location and the points re-gapped to the normal .014” or so. The adjustment slots were at the end of the travel, but it was just enough to get them into specifications again. With the point plate shifted appropriately, the firing marks lined up once more. The engine covers were re-installed and the bike started on the first kick. Well, that problem was solved, but the neutral light hadn’t worked since the bike was put back together again. Opening the headlight found a bulb socket with a tiny blown 6v bulb at the end. These are very uncommon bulbs, not to be found at an auto parts store. Digging back into the S90 spares, the old speedometer had the bulb and socket/wire still attached. Luckily, the bulb was still okay and finally the neutral light turned a nice soft green color again. That was as far as I could go with the bike, so I took the tools back to the shop and awaited my customer’s arrival.

After his test ride and inspection of the paperwork I had on the machine, we tried to wedge the bike into the back of the Toyota SUV. Unfortunately, the back seats did not fold down fully, but did tip forward somewhat. We had drained the gas tank and removed the battery so the bike could lay on the right side away from the crankcase vent passage on the left. The rear tailgate wouldn’t close so the front wheel was removed while the bike was lying in place and that gave enough room to close the rear door safely. Finally, an hour after their arrival, the happy couple drove off into the horizon with the CL90 nestled in the back of their rented Toyota Highlander. Their next stop was Sea World, then off to San Jose on Saturday where the little CL90/S90 hybrid will find a new home with an enthusiastic owner.

In the end, I think I broke even just for the investment in parts and services while the bike was revived. If it had been a customer repair job, the labor charges would have been close to the selling price alone. While being retired doesn’t require that a profit be made on every one of these rolling waifs, I do need to be a lot more selective about what to revive and what to let go as-is with a “Sorry, I can’t do that this time!”

Give’m what they want…

Tuning/repairing old vintage Hondas (and other makes/models) often requires going beyond whatever it says in the factory repair manuals. When bikes are brought back to life after many years, sometimes the process is straightforward and direct; clean the fuel system, replace the battery, adjust the valves, set the ignition timing and off you go! Other times, they defy all the standard settings and you are on your own to discover the blocks to a good running machine.

My recent experience with swapping a rebuild S90 engine into a CL90 chassis lead to many problems, just from a design and structural viewpoint. The “early” S90 has a different set of engine cases, intake manifold system, exhaust port angles differ, different clutch cover, dyno cover and other smaller features which created parts problems and finally required re-rebuilding the engine using the correct matching CL90 engine cases. Even though these 90cc OHC engines were part of a long-running design, substantial changes occurred in the first year or two and that created more problems to be considered.

Once the engine components were swapped back into the stock cases, the carburetor settings were different from one series to the other, calling for careful tuning steps to be followed in order to get the bike running properly again.  At first, the engine was running rich (starts with no choke) and fouling the plug, while wafting a bit of oil smoke out the exhaust pipe. The engine wouldn’t take even half-throttle with no load on it. Backtracking on my adjustments, it was discovered that the point gap was out around .018” instead of the normal .012-.016” settings. This can cause a loss of coil saturation and subsequent misfiring that can mimic carburetor problems, if you aren’t careful and observant. In trouble-shooting and/fine tuning efforts, you have to make ONE change at a time, re-evaluate and then try something else if necessary. In this case, the point gap wasn’t a significant issue, so I moved onto the carburetor settings.

Current “wisdom” is that with today’s fuels, you need to richen up the fuel curve about 10% in order to compensate for diluted gasoline energy potentials. In several cases, I have found that the carburetors needed to be richened up about one main jet step to help smooth out the fuel delivery to the engine. I had raised the needle up one notch and was using the stock S90 main jet which was #90. With continued richness on the plug and poor performance, I lowered the needle and re-tried the engine performance once again. There was little or no change, so the main jet was reduced to the stock CL90 size, which is #88. Each time there was just a little cleaner running, but not anything that was really acceptable. Dropping the main jet to #85 seemed to be the magic setting, as the engine started to run cleaner and without the mid-range hesitation.

This may or may not be the final answer in that the air filter is a simple conical unit, standing in for the stock air cleaner/filter setup which was not available with the bike. Once the original S90 engine configuration was altered, the air filter for the S90 was no longer compatible with that of the CL90. More run-time is needed to confirm that the engine is set properly and won’t seize due to an incorrect main jet choice. Sometimes, the changes to the carburetion are masking an ignition system problem. In several cases, I have discovered that a bike will start and run at idle with a failing ignition coil, but when the throttle is cracked open a big misfire occurs and the bike fails to move forward with authority.

One of the other steps was to check the spark plug cap for high-resistance. This specific engine still carried its “Hm” logo’d spark plug cap, which are generally viewed as “non-resistor” types. When this one was checked, the resistance value measured was 33k ohms; whereas the “resistor” style plug caps have only 5k ohm ratings. Swapping out to a new resistor cap helped the performance to some degree, as one of the trouble-shooting steps. It is beginning to appear that many of these spark plug caps might well be faulty as they age and go through many heat cycles.

The ignition coils on the OHC 90 engines are mounted directly to the top of the engine cases, along with the condenser. You can check the primary winding ohms values by disconnecting the engine wiring connector plug and probing into the black wire terminal. Disconnecting the points wire connector allows for access to the other end of the primary windings set. So a probe into the black lead and one in the disconnected points wire connection will give you a reading of the primary wiring ohms resistance. If you need to service the condenser or replace the coil, the motor will have to come out again; or at least be tipped down off of the lower rear mounting bolt.

For the moment, the bike is running smoothly and may have a new owner waiting in the wings who can help take it to the next level. Given the amount of money spent on new parts to make the bike fully functional and the time invested in multiple engine work efforts, it will definitely not go down as a money-maker for MrHonda. It did provide a good platform to continue to hone my tuning skills, though, and perhaps some of these tips will resonate with my readers out there who are wrestling with similar issues. If they won’t run on the OEM spec settings… give them what they want!

Equilibrium restored, sparks recovered, pumps are pumping now...

Since the last installment, the CBR900RR carbs were re-checked; installed with rerouted emission control hoses and a new petcock/screen installed on the fuel tank. Initially, the fuel pump relay connector was jumpered to get the pump to function, but once the fuel bowls were filled, the pump slowed down like it normally does as the demand slackens. Once the bike was fired up, the solid-state fuel pump relay was re-installed on the connector and miraculously the pump functioned normally, apparently as designed. It won’t fill empty fuel bowls, but once the engine is running, the pump relay does function normally. All’s well that ends well and the bike was driven out on Sunday afternoon and apparently made the trip back to the owner’s house successfully, in one piece.

The little devil of a Sport Cub C110 was treated to another condenser, which was actually designed for a different application and a replacement ignition coil from an eBay seller. Once the flywheel was re-installed, the bike showed a nice bright spark at the coil’s wire end, but the “fits Honda CA110” eBay auction page failed to note that the spark plug secondary wire is about 4” too short. The original application was for a Bridgestone 90, which shared the same mounting points, but the primary wiring was reversed and the spark plug wire was too short for the Honda application, so it is headed back to the seller next week.

The old coil was reinstalled and suddenly was working just fine. The bike lift was lowered down so the bike could be kick-started from ground level. Initially, the bike kicked over but didn’t fire off on full choke or no choke. After using various throttle settings, suddenly it lit off and ran just fine with no unusual sounds or leaks, so success has been achieved there this week, as well.

The CL/S90 project was treated to some shorter aftermarket shocks, which required some bushing modifications, but now the rear wheel is well clear of the ground, making it sit better on the centerstand, which does have a slightly bent leg on one side.

Fitting the CL90 exhaust system to the bike left one problem which really has no easy solution. The S90 engine has a high-mounted dipstick on the clutch cover. When the CL90 exhaust was engineered for these frames and engines, the exhaust pipe runs right over the top of the dipstick handle. So in order to check the oil, you have to loosen the exhaust pipe. The normal solution, if you had a later model engine would just be to change the clutch cover to the CL90 style, but that doesn’t work here due to the different oil passages in the center crankcase that don’t match up with the clutch cover.

A few days later…

I pulled the engine back out of the S/CL90 and went forward with rebuilding it in the correct CL90 engine cases. There was a lot of cleanup to do as they had been sitting out in the open at an auto body shop gathering resident dust as well as sanding dust from years of bodywork efforts nearby. The center cases, clutch cover and dyno covers were all cleaned and flushed out in preparation for assembly with the majority of the S90 engine parts. However, there was, of course, an issue with the right side engine case where the kickstarter stopper is located. Sometime in its long life, the stopper had been sheared off inside the cases. The S90 engine was torn down and that case half taken to my good friend Rob North for some welding on the broken case half. Using the S90 case for a guide, he was able to Heli-arc the stopper back to near factory shape in the CL90 case half.

Once that was out of the way, the rest of the engine internals were swapped into the correct case set and eventually the reassembled engine was installed back into the chassis. With everything buttoned back up again, the start-up drill was initiated… and failed. Again, there was no spark at the plug nor was there a viable voltage signal at the points. I imagined having to pull the engine again to recheck the ignition coil/condenser components, but when I disconnected the point wire at the connector, the voltage re-appeared. For some reason, the old points tend to ground out at the wire connector when clamped down too hard. Readjusting the wire connector on the points brought the power back to an ungrounded state when the points were opened. With spark reestablished, the engine fired on the first kick, sounding happy and healthy once again. Now with the dipstick in the proper location, the oil can be checked and filled without difficulties.

A near-miss CBX purchase almost happened last week; but once I took a closer look, I decided to pass. The bike had 48k miles on it and the suspension was pretty loose on both ends, plus the engine had not been run for a couple of years, the tires were bald and rotten and the whole thing looked like a financial black hole. Hard for me to turn down a CBX, but I did!

Good news, of sorts, in that the grubby XL200R found a new home, basically for the cost of parts invested over the past month. That was another one of those deals best left alone in the future. Lesson learned!

The little C110 Cub is getting closer to street-legal status now. With a running engine and newly revamped clutch, all that was left were to hunt down some footpegs, which came from an eBay seller for very little money. A search back through my friend Ron Smith’s storage locker turned up a spare fuel tank and the chromed side covers for the Sports Cub so it’s looking better all the time now!

Bill “MrHonda” Silver