Monday, March 20, 2023

Mechanic to the stars…. Sort of

Those of you who follow the comings and goings of bikes, in my care, may have seen the 1965 CP77, which I wrote about last year and could have owned (but didn’t), go through BAT auctions for $31k recently. Records were produced that showed the bike being given to Solar Productions from AHMC as a “promotion” gift and DMV paperwork also verified the ownership of Steve McQueen. How AHMC got their hands on a non-Police CP77, which is not a US model, and passed it along to Steve will always be a mystery. When I had the bike here, it required rebuilding the seized engine, full fuel system clean, adding new tires, cables, and a battery to make it run again, but no other restoration of any degree was performed.

See: for details on that one.

My friend Don, who is a wrangler of bikes and deals with the rich and famous
(and was the middleman for the CP77 repair work) then brought by a very innoculous-looking white 1964 Honda Cub 50, a few weeks ago. It had an oil leak, the ignition switch was damaged and when it did run, the rear tail light filament wouldn’t light up, even though we put in a new bulb and a 12v test light showed power getting to the bulb socket contacts.

                                                    Factory C100 photo, courtesy of AHMC.

Anyway, after receiving a defective 6-wire ignition switch from Thailand, the replacement arrived within 10 days and proved to be a better candidate for the bike’s ignition system issues. Several problems were resolved after removing an extra ground wire that had been installed which kept the neutral switch ON and the brake light circuit energized even with the ignition switch OFF. The wires were reconnected properly (these are unusual bikes in that they have a fuse on the ground wire of the battery, instead of the + positive side and the ignition switch opens the ground circuit instead of the normally hot side of the wiring) and the neutral light/brake light problems were eliminated.

The tail light function problem was resolved when I used my 12v test light to ground the tail light bracket to the engine and then the light powered up normally. Despite being bolted firmly to the rear fender, somehow the paint on the tail light bracket and the rear fender kept the bracket from grounding properly. Removal of the bracket and a bit of paint solved the grounding issue, which apparently must have been present since the bike was built.

There was another problem with the new headlight bulb only working on high beam. After disassembly of the dimmer switch, which takes watchmaker skills, nothing was seen to cause a problem with switching from LOW to HIGH beam, so a further check discovered that the tang on the headlight bulb was installed into the reflector in one of the three socket slots instead of the index slot. Turning the bulb a half inch solved that problem, as well.

The big oil leak proved to be due to the thick, but original shift shaft seal. For $8, an eBay seller provided just the right seal and the leaks underneath were reduced to nearly zero after it was replaced. The magneto and rear chain cover had to be removed to access the seal more easily, so I nudged the ignition timing a bit more advanced than it was before, through the access holes on the flywheel.

With the little bike up and running, charging and lighting up properly, Don came back to fetch it again. He said that the bike has been traced to the estate of Grace Kelly. Apparently, Honda shipped a white and red C100 Cub to their address in 1964. It is uncertain as to whether Grace Kelly actually rode the bike or not. There was no license plate on the bike and no indications of ownership. It just looks like a plain white 2,600-mile C100 Cub 50 with a nice fresh seat cover and new tires. You just never know what the story is behind some of these vintage Hondas.

Coming soon… Another Steve McQueen vintage Honda story…

Bill Silver

aka MrHonda

Monday, February 20, 2023

A Tsunami of Scramblers…

It is interesting to watch as waves of certain bikes come to me in cycles mostly unexpectedly. Last year it was a set of CB77s that came through the shop, including my ill-fated white CB77 purchased from Mecum auctions in 2022.

For the past few months I have been rebuilding a “special” CL77 that belonged to a celebrity a long time ago. The bike looked like a $50 parts bike when received and 90% of the engine was replaced. The chassis was all beat up and missing about 60% of the parts. Through various contacts, friends and eBay sellers, it is slowly coming back together, but continues to confound me with mysterious assembly issues.

Not long after the CL77 project arrived, a man from Visalia, CA (about 300+ miles away) got my name from someone else and desperately needed to have his 1963 CL72 engine overhauled. He has family down this way, so it wasn’t a complete trip just for the motor delivery. He dropped it off and it looked very dirty and sad on the outside, only to discover that the insides were worse. Like the project bike mentioned above, most of the engine internals needed to be replaced, including the crankshaft, cylinders and cylinder head, transmission and clutch, due to water damage.

During the same time, another man had been messaging me from the Santa Cruz area with CB92 clutch difficulties and wanted to bring it down for repairs. He also had family in the county, so it was also a dual-purpose trip. When he dropped off the CB92, I was just cracking open the CL72 engine and wondering where I was going to find a donor motor to fix it with. Fortunately, we both knew a friend in the Santa Cruz area who had CL72s stuff. He had given away most of it, but still had a motor sitting in storage that actually turned over and offered it to me for FREE! All I had to do was to bring it down here. So, once the CB92 mysteries were resolved, the owner picked up the CL72 motor and brought it down, then loaded up the Benly for the return trip back to Santa Cruz. Sometimes, it takes a village to get stuff done like this…

So, with a mostly finished CL77 project on my rack and a CL72 engine on the bench, a local friend decided to sell his 1966 CL77 which had been stored in his garage for the past 13 years! The bike was a partial restoration with about 11k miles showing on the odometer. So, on a swing past his N. County home for my monthly chiropractor appointment and a stop in to look in on my friend’s ailing CB350 (another mystery bike), I scooped up the 305 Scrambler and brought it home with instructions to go over it and make it run again.


Day One…

This bike presents itself nicely but has the usual patina in the nooks and crannies of a mostly original machine that had a cosmetic rework to the tank, fenders, and side covers, along with reworked wheels and a set of aged K70 Dunlop tires installed many years ago.

I checked compression and the readings were close to each other at about 140-145 psi, which is a bit on the low side, but this is a post-65 bike where Honda lowered the compression from 9.5:1 to 8.5:1 to lower the risks of piston seizures. The next step was to remove the carburetors, which had been drained back in 2008 along with the fuel tank. Lifting the slides out of the carburetors, I noticed that the needles were bright brass colored, indicative of KEYSTER carb kit parts. Sure enough, they were marked with D13 instead of the desired Kxxx numbers. The old spark plugs were supplied with the bike and they were quite fuel-fouled so it was looking like an uphill battle to get this bike running well again. NOS needles are NLA these days, although I had scored a set of them for the project bike before the seller ran out.

With the air filters removed, exhaust pipes loosened up to get the left side air filter cover and filter removed, the carburetors came out looking a little bit scaly, but serviceable. Back on the bench, the problems were revealed. One of the floats was bent sideways, hitting the inside of the float chamber, and was dented in on one side. One side had the correct 22.5mm float level and the other one was sitting at 28mm! They did have OEM jets installed, still, but there was scale inside the fuel inlet passages and one float bowl gasket was displaced at the front, no doubt causing a fuel leak when fueled up. One of the carb insulators was chipped out where the o-ring channel was formed, so that was probably another issue that caused running problems in the past. Once the carburetors are sorted out and reinstalled, attention will be focused on the ignition system.

Day Two

After several hours of cleaning, replacing parts and reinstalling the carbs to the bike, I hooked up my remote fuel bottle to the carbs. They promptly leaked at the bowl gaskets. Of course the worst one was on the left behind the pipes and next to the oil filler tube. After trying to replace the gasket again, I unhooked the carb, studied the gasket surfaces, changed to another gasket and changed the spring that holds the bowl up to one with more tension… No luck, it keeps leaking.

Prior to fueling up the carbs, I had statically checked the ignition timing after resetting what seemed to be a loose timing chain. There was a lot of slack at the crankshaft when turning it backward and forward to set the ignition timing. The timing was retarded and I suspected that the camsprocket weight springs were stretched and the timing was over-advancing when the engine was running.

I let the carbs fill to where they began to leak then shut off the fuel flow and started the engine. It lit off pretty easily but there was a bit of backfiring in the exhaust (straight bikes with Snuff-or-Nots installed) and the engine didn’t want to idle down smoothly. Checking the timing advance with my automotive timing light revealed spark timing issues as suspected. Retarding the spark timing to rein in the advance back to the II marks on the rotor left the idle timing near TDC (T mark) not at the F mark. And the left side was not advancing as far as the right side. Theoretically, both sides should advance the same amount because both sets of points are running off of the same point cam, which is extended into the right side camshaft and plugs into the slot in the spark advancer plate.

With the engine shut down, I took at a small pointed screwdriver and pushed the end of the point cam around and saw visible side play, which translates into a change of the point gap when the engine is running. Because the rubbing blocks are set at 90 degrees from each other on the point plate, there is a moment where both rubbing blocks push the point camshaft a little bit sideways and when wear occurs (speedo showed 11k miles), the point gap for the left side is different than the right side depending upon how much wear is in the shaft to camshaft bore. This side-play, coupled with the slack return springs on the spark advancer unit results in inaccurate ignition timing and uneven spark timing at idle to compensate for the over-advanced condition. So, the only fix is to replace the point cam and/or camshaft that it rides in, plus replace the advancer weight springs. What often is seen is that the camsprocket which contains the spark advance weights and springs works loose on the rivets that hold it together. The camchain sprocket starts to rock back and forth on the rivets and the ignition and cam timing are compromised. Sometimes the weights are worn at the pivot points, as well, so there are a lot of places for slack to develop in the ignition timing system.

Two possibilities for alleviating the timing problems to some extent are to install an electronic ignition plate that is magnetically triggered and doesn’t apply pressure to the point camshaft as it all turns. This can minimize the unequal spark timing from side to side, but doesn’t address any advancer spring slack or weight wear on the pivots. Beyond that, the cure without tearing the engine down is to install a crankshaft-mounted ignition system from a supplier in Germany, which is highly effective but costs about $500.

So, after consulting the surprised owner, I offered to remove the cylinder head top cover (which you can only do on a Scrambler with the engine in the chassis) and inspect the camsprocket springs and weights.

Day Three – problem-solving

I grabbed a bunch of wrenches and some paper towels, then went to work in removing the top engine mount from the frame which holds the condensers as well. I removed the spark plugs to reduce the chances of the pistons pushing the top end up off the base gasket, which causes a leak. With the top cylinder head cover off, the baffle plate was found to have been glued in place with Hondabond type of grey adhesive. The cover was pried up a little at a time which caused the gaskets to tear anyway. Once the baffle plate was removed, the camsprocket springs and weights were checked for any slop and wear. In this case, the first advancer weight and spring were actually pretty snug, but when the point cam was turned, the weight didn’t spring back to the beginning position. I turned the motor over with the rotor bolt and checked the other spring/weight. The spring looked like it had been poked with a screwdriver or something to upset the coils and lessen the tension on the weight. I hadn’t tried a “springectomy” with the engine in place before, but doing it on a Scrambler is the only possibility.

The end of the spring was partly lifted up with needlenose pliers and the loop pulled away from the mounting post. The spring needs to be turned 90 degrees to unhook it from the back side of the advance weight. I had stuffed paper towels in and around the camsprocket to prevent any unexpected drops into the cylinder head or the camchain/rollers. Fortunately, I had a NOS return spring in stock, which is used on the CB/CL camsprockets. The Dream sprockets have larger weights and lighter springs to allow for an earlier spark advance curve. With some careful use of the pliers and a hook tool, I was able to hook the spring on the weight, turn it and loop the other end up over the post successfully.

Checking the spring action on the weight gave the desired return function, which was verified when the ignition timing was rechecked after the reassembly of the top cover and gaskets. I used GasketCinch to reglue the gasket surfaces back together and while I was waiting for the glue to set up, I attacked the carburetor one more time. All the surfaces were clean for the gasket to seal the bowl, but something else was working against me. When I rechecked the float level, it was at 22.5mm but the float itself was bouncing up against the roof of the float chamber. I have observed that when the Keyster kit float valves are used, there is some dimension that causes the floats to bounce off the top of the float chamber when the level is set properly. I dug out a good used 2.0 float valve that had a “K” stamped on it (Keihin) and tried it with the rest of the parts and surprisingly the float had an extra 1/8” of clearance before it could be pushed up to the roof.

I hooked up my fuel line system to the carburetor, while it was still off the engine to verify that it wasn’t leaking any further and it had indeed stopped seeping as it had previously. I went ahead and reinstalled the carburetor, hooked up the air filter, installed the left filter cover and then reattached the loosened exhaust pipe set for the 5th time. With the remote fuel bottle feeding the carbs, no leaks were detected! I kicked the engine over and it started quickly, finally settling down to a mostly normal idle. I rechecked the ignition timing with my Sears timing light and had to back the spark timing a little bit more, still with the full advance coming right into the II marks on the rotor, so at that point, the mission had been accomplished.

I installed the fuel tank and seat and added some fuel to the tank for a test ride. The tires had 5 lbs of air so they were reinflated and off I went for a test ride that took about 10 minutes. The bike was a little bit cold-blooded and was snapping back at the exhaust pipes at part throttle. It pulled well under power and went through the gears cleanly. It’s possible that the heavy clutch pull is the result of a Barnett clutch pack and springs, but when I put it in gear with the clutch lever pulled in I could stop the rear wheel with the foot brake pedal and the engine didn’t die.

The spark plug wires had been replaced and a set of SPARKY plug caps were installed on the plugs which require the screw-on tips to make a good connection. The wires were a little bit on the short side and when I looked back into the plug caps I noticed that the little coil end of the plug cap hadn’t been fully pushed through into the corner of the cap, so the spark plugs were getting arcs from the displaced wire ends instead of being solidly attached to the plugs.

The test ride was good overall but the speedometer needle immediately went to 100 mph as I was cruising down the road at about 45 mph. I recommended that the unit be sent to Foreign Speedo, here in San Diego, for one of their meter overhauls in the near future. The bike is for sale, so the new owner might wind up handling the speedometer problem after being informed or seeing what happens on a test ride of his own prior to purchasing.

I loaded up the bike and sprinted up the highway at 2pm which can get busy around that time, but I managed to make the 28-mile trip in 35 minutes and the return leg only took about 45 minutes, which was a relief. The owner had some extra muscle available to help me unload the bike and I lit it up for them and ran it down the road under power with the Scrambler pipes rattling the neighborhood.

I was concerned that I was going to have to tear down the engine to get the camsprocket out and have it sent out for repairs, but with a little patience and some careful work, the end result was a revived CL77 which had been awakened after a 13-year slumber. It feels nice to see it back in action again.

Bill Silver   aka MrHonda  


Thursday, February 2, 2023

Vintage Hondas… Expect the unexpected

You can bet your sweet S90 that it will be a surprise along the way.

                                                              1965 Domestic Honda S90

If you stay in one place for a long time and work on a lot of local bikes, at some point in time one of them will come back around again. So, when the “Honda S90” listing on Craigslist showed up I was intrigued but not triggered to remember the bike from my past. A quick message to the owner yielded a response that went, “You worked on this bike 10 years ago.” Hmmmm???

We made an appointment to meet up about 15 minutes away and the bike was in a pretty sad state once you got close to it. Both tires were flat and off the rims, the engine appeared to be seized, very old gasoline was still in the fuel tank, the battery was dead and it was obvious that the bike was actually a JDM domestic version judging from the tail light, solid passenger pegs, low handlebars and a side stand that was factory attached to the footpeg bracket. The speedometer was in MPH, but it didn’t have a neutral light function, just a high beam indicator and a meter light. The headlight switch had only a H-L setting with no on-off function, so there were many puzzling features as the investigation continued.

We struck a “reasonable” deal price and the owner’s husband helped push the poor little dead S90 up the driveway, from behind the apartment building and into the back of my Tacoma. The bike was pretty complete, but the wheel hubs were all chalky from sitting somewhere wet for a long time and the rims has rust pits in various places. I was told that the bike had been run for a while, but judging from the virtually unused front tire with a 2011 date code, it didn’t go very far. The bike didn’t have a title anyway, nor a license plate, as it was a project bike at the time, made from various parts which became more apparent as time went on.

While unloading the bike from the truck, the shift lever got bumped and the engine engaged, turning backward, releasing whatever the stuck piston was doing previously. I resolved to remove the engine and take a close look at what had happened to it, while starting a parts order for tires, tubes, and a battery to get things started.

With the stock muffler removed and the intake manifold/carburetor taken away, the engine drops out with just three bolts. I hauled it up on my bench and proceeded to dismantle the top end fearing the worst. But as it came apart, the piston crown was mostly shiny from low hours, but signs of water intrusion were present. The cylinder had some staining, but the piston wasn’t seized, although the top compression ring was kind of stuck in the ring land. A little penetrating oil and some careful movement freed the ring and it appeared to be good enough to reuse again. A quick hone of the cylinder was done to rough up the surfaces just a little bit.

The cylinder head was more of a mess. Old valves were cupped and water had gone down in the intake port where it etched away at the metal just behind the valve seat. New valves were ordered and the seats were re cut with my ancient set of OEM valve seat cutters. Fortunately, the seats had enough material left to allow for valve seating, so the head was reassembled and installed back on the engine.

A new clutch cover was ordered from as the original was broken where the clutch cable is secured. There are two different clutch covers, depending upon the serial number of the engine, which was harder to determine as there were no serial numbers on the engine apart from the cast in S90E and the space below was blank.

The wheels required some cleaning and the brake drums scraped clean with a screwdriver blade then wire wheeled and finished with a Scotchbrite pad. A set of inexpensive scooter tires, tubes and rim bands were ordered from an eBay seller, so they were spooned on after de-rusting the rims as much as possible. New brake shoes were ordered from an eBay seller for very little money, having come from China.

One fork seal appeared to be leaking so the forks were removed when the wheel was taken off for tire replacement. The right side fork had a screw-on fork seal holder, but the left side had a conventional fork slider with the seal retained with a snap-ring. When they were reinstalled, it turned out that they were different lengths! I wondered why the axle came out with some difficulty, but now it was apparent what that was the case. The difference was probably about an inch with the forks uncompressed, but pulling down on the front end finally matched them up enough to insert the axle once again. I have to say that I haven’t run across that problem before! Either the long fork is from a later version or perhaps from a CL90 bike instead. Finally, the front brake cable was excessively long. The early low handlebars take a shorter cable, of course and someone just ordered a high bar US version. The clutch cable was the correct length, however, as was the throttle cable

The ignition coil was replaced due to a cracked spark plug wire and general age-related damage. Once everything was correct, the little engine was wrestled back into the frame. The fuel system was next on the list so the Chinese copy of the original angled base carburetor was cleaned, which was a type that Honda used on the early engines connected to the head with a twisted intake manifold. The early carb setup requires a unique air filter and connector to put it all together. All the parts were connected originally, so it is puzzling how water had worked its way down into the intake port.

So, just when you think you have it all sorted out, the unexpected happens… The compression tested out about 130 psi, which is about 20 short of normal, owing to a less-than-ideal valve seat repair attempt. Still, it should have at least started up, but when the battery was checked, it was down to 3 volts from six. Given that the only thing that can drain the battery down is the rectifier, it was apparent that it would need to be changed. And to change the rectifier, you have to remove the engine.

I recharged the battery back to 6 volts and installed it without hooking up the rectifier, just to see if the engine would start up. I had compression, spark, and fuel in the carburetor, but it wouldn’t even give any signs of life. The spark plug appeared to be dry despite all the kicking, so the carb was removed again for a check of the idle jet and passages. Everything seemed to be in order, but it didn’t affect the starting routine at all. Kicking the engine over with the spark plug out I noticed that the spark was erratic at the plug. The spark plug cap tested normal, so all that was left was the possibility that the condenser was failing. Apparently, the part that was failing was my brain because when I assembled the coil on the top of the engine case, somehow I failed to reinstall the condenser! Of course, in order to check the coil and condenser, you have to remove the engine again.

To cure the compression issue, I removed the head again, stripped it of all the valve train stuff and took it to my local machinist, who cut nice fresh valve seats to match the new valves for $25. When the engine was reassembled the compression jumped up to 150psi, which is in the range of factory specs. Sometimes, the DIY efforts are better left for the professionals.

In the meantime, I ordered a cheap rectifier from an eBay seller who modifies those little solid state cube bridge rectifiers like Radio Shack used to sell for a couple of bucks. The unit was already made up with long proper colored wires, but when I went to install it the mounting bolt was just a round 6mm bolt and the hole in the chassis is half-round! So, at that point, the options are to either drill out the frame hole or grind a flat on the bolt. I put the bolt on the grinder wheel to make it flat on one side, but when I tried to install it, the bolt proved to be too short! Back to the shop to find a longer bolt or screw, which I found in a 6mm Phillips screw from my drawer of fasteners. I had to regrind a flat on the screw again and finally got the little unit to fit back into the frame hole.

The problem with these little S90 engines is that they are just kind of egg-shaped and it is difficult to find a nice flat space to use to raise it back into the frame without it wobbling all over the place in the process. The engine harness plug is tucked up way inside the frame, so you have to reach up and plug it in carefully while balancing the engine on a stand or jack. Finally, with a condenser installed and the new rectifier bolted up, the three mount bolts were inserted and the rest of the fasteners were installed.

Having charged the battery once more, it was installed and hooked up to the new rectifier and the bike was ready for another starting attempt. Not surprisingly, once a proper condenser is installed, the bike lit off on the second kick, as it should.

A final challenge was the fuel tank and petcock. The tank had been sealed with Kreem about 10 years ago and that product doesn’t really hold up in the long term. Plus it looks like they just poured it over the top of existing rust so the insides had been peeling away from being exposed to old gasoline left behind the last time it ran. The petcock brass tube was gone, eaten away by corrosion. I cleaned out the passages and installed what I thought was a new 4-hole petcock gasket, but apparently, it was used in the past and had hardened enough to allow gasoline to slip past the surfaces of the seal.

The correct petcock for the early model S90s is difficult to find now, as it has a crossover tube to connect the bottoms of both sides of the fuel tank together. There are numerous Chinese copies of these petcocks as they fit a number of models. There are variations with an outlet that points down, points sideways, with and without the crossover tube that also points in different directions. What seems to be the problem is that most of the fuel line fittings for these copies are for a 4mm hose instead of the 5.5 mm hose that is needed to connect the carburetor to the petcock. These petcocks are dirt cheap, so I ordered one similar to the one on the bike, which didn’t have a crossover tube fitting, just to get something fitted up to allow the fuel tank to be installed so the bike could be test-driven. Unfortunately, the first try with an eBay seller yielded the wrong version despite the fact that I had ordered the correct one to match what was on the bike now.

With the engine back in the chassis and the chain hooked up, I confirmed that the transmission is a rotary gearbox design, which is great for around-town traffic, but not if you were going to ride it in some kind of competition. The gear pattern is N-1-2-3-4-N going down, down, down, down. You can, of course back shift it to gear down, but not paying attention to the transmission in 4th gear will get you into neutral at a high speed and if you push down again, you get 1st gear when you are going 50mph. So, you just have to override your normal shift pattern in your mind to compensate for this feature.

Finally, once the bike was running and safe to ride around the block, the first thing I notice is that the clutch is slipping! I thought it felt a little off when I was kick-starting it so much, kind of not catching the engine fully and the suspicions are confirmed! Another order to DSS for some clutch plates and a few days of waiting to install them. Ordinarily, these little clutch packs are pretty bullet-proof, but not knowing the full history of the engine can lead to more surprises when it comes down to getting the bike to go down the road.

Removing the clutch revealed that one of the friction plates deteriorated so it looked like I had three steel plates and one friction plate. All the friction material was gone from the plate and bits had lodged around within the clutch hub. New parts were installed after cleaning out the old debris and suddenly I had a bike that kicked over smartly and didn’t slip when power was put to the motor. That one should last for years to come.

Historically, the OHC 87cc engine had a 20-year run of production. It replaced the pushrod C/CT200 engine in 1964 and wound up expanded in the CT110 models for the early 1980s. Going over the parts lists for the S90s is a real head-scratcher. There are three sets of engine cases, two clutch covers, different oil pump and filter screens, two series of transmissions, different cylinder heads, intake manifolds, air filter systems and carburetors. By the time the CL90 versions came out in 1967, most of the major redesigns were completed, but the early years of the Super 90 are full of modifications and parts that are not interchangeable with later versions.

Apart from the Chinese copy carburetor, which is unique for the early models, the other modification to the engine was a “performance” camshaft from which is a $40 investment. I have used this cam in conjunction with a big bore piston kit on a couple of CT90s and it really woke them up. The cams are a drop-in modification, having extended cam timing but no changes in the base circle or valve lift.

Electrically, the light bulbs were all blown out from someone running the engine without a good battery in place. Typically, the US bikes have a headlight switch has an ON-OFF, LOW, HIGH function all built into a single unit. The domestic bikes only have a HIGH-LOW switch on the left side and no separate ON-OFF switch function. That is controlled by the ignition switch which has OFF-ON-Lights settings instead. The unique domestic tail light has its own mounting bracket, lens unit and base not commonly found in the US. The original turn signals were MIA. The low beam of the replaceable bulb was burned out so DRATV came to the rescue once again.

In order to get the bike registered in CA it has to have an engine number, which is missing on this machine. California has its own CA-assigned stickers that are applied to either the frames or engines when cases like this occur. That will require a separate trip to the CHP office after the first go-round with the local DMV office.

Slowly, but surely, the bike is coming back to life and full function once again. Even tiny little bikes like this can consume a lot of time and effort to revive. S90s require attention to detail and a close study of the various superseded parts that were made as production increased through 1969.

Honda finally replaced the venerable, horizontal OHC 90 series machines with new CB/CL100s with upright cylinders, followed by a 125cc version, which also included the SL100-125, the one-year CT125 and eventually XL100-125 singles, all fitted with a 5-speed transmission. The basic design morphed into later XL185-200 and XR200 versions. The 90s did do extended service in the US90/ATC90-ATC125 three-wheeler models until 1985, so the linage of the original design carried on for more than 20 years.

Bill Silver aka MrHonda


Saturday, December 17, 2022

Frankenbike 4.0 revisited again...

Just when I thought we had a handle on the bike’s reliability, new problems surfaced. Jake reported that the bike died on him while driving back from a 20-mile ride. It blew the fuse and he attributed it to the 60/55-watt headlight that had been installed by the previous owner/builder. Fortunately, he had a spare fuse with him and was able to change it out and make it back home again. The battery kept going low and he had to take it to the local auto parts store to recharge it every few days while running with the lights OFF as much as possible.

I was back for my monthly chiro appointment, just down the street from where he’s been living; still in his dead Prius car next to the railroad tracks. I stopped by to check the bike out and we confirmed that the headlight H-4 bulb was too much for the charging system, then with the bike running, it was apparent that there was little or no output from the stator. In the back of my mind, I thought that I had a CB350 stator and a 35/35 H-4 bulb at home so developed a plan to come back and install them.

Honda’s later model stators run in oil and ones for 350-450 and even the 160s are similar in design, at least from a quick glance. They all have little pigtail wires for the nearby neutral switch and have a round plug that meets up with the wiring harness. It’s a 70-mile round trip from home, but the continuing problems with the bike spurred me to gather up my tools again and haul the critical parts back up to N. County to help keep this man on the road with something other than his beach bike.

I really don’t spend a lot of time with 350 twins, at least by choice, so wasn’t deeply familiar with the differences between the stators of that era. The one I had in the shop came to me years ago from an unknown source, but it tested out fine and I was confident that it would solve the problem. However, it wasn’t quite as easy as I had hoped…

I met Jake at his little camping spot where the bike had been used sparingly for the past few days. I leaned the bike over against my truck’s tailgate to keep the oil inside the engine once the stator and cover were removed. I had replaced the inner gasket previously and hoped that it was still intact when I removed the parts. Fortunately, it was still solid and was set aside while I removed the stator from the cover. I noticed that the stator had a burned spot at one of the coils and that was what was grounding the output. I pulled out the old one and went to install the replacement only to discover that while the OD and ID were correct and the wiring connectors were a match, the replacement stator was much thicker and all of the mounting holes were not threaded which was needed for the 350 covers. It looked like some longer bolts might secure it to the cover, so after a short walk to the local Auto-zone. That was a waste of effort as they didn’t carry any loose bolts of any kind in the store, so we moved the bike away from the truck with a rag in the engine case drain hole and drove to Home Depot for hardware.

I found some longer bolts and nuts/washers at the store and headed back to the bike, which was about 5 miles away. The bolts looked to work fine, but then when I tried to install the dyno cover, I discovered that the lack of threaded holes kept the cover from being installed! So, one more trip to Home Depot to get some oval screws for the cover and nuts lead me to assemble the whole cover together from the inside, so the next time there is a need for accessing the rotor for timing, etc. the whole assembly will have to be removed again. It’s a stop-gap repair for the moment and I still have no idea of what the stator actually came from originally, but in the end, we had a charging system that was building the 11 volt battery condition up past 12 volts with an increase in the RPMs.

We had changed out the headlight bulb already, but I went back into the headlight shell and jumpered the yellow and white/yellow wires from the headlight switch to kick in the extra AC lead power back to the rectifier/regulator unit and the test results were even better. What was envisioned as a 30-minute repair job ended about 3 hours later, but with a successful result. Checking eBay for stators, there were a number of correct ones available for less than $50, so we’ll grab a good one for the future and have it handy for any future repair moments.

The bike is now much happier to start up and run well now that there is a current of voltage feeding the battery. It’s hard to know what the next challenge will appear, but for the moment the bike resumes its transportation duties and gives Jake some new options for continuing his photography business. Hopefully, some new opportunities will arise to help him get back into stable housing and get his dead car repaired. He really has an amazingly positive outlook on life, despite all of his current woes.

I’ve certainly learned a lot more about the CB350 twins than I had imagined, but it all comes in handy at some time, especially in cases like this. Now, just what does that stator actually fit…..?

Bill Silver

aka MrHonda


Tragedy.. Frankenbike gets run over

Maybe it needs an exorcism or some kind of spell breaker, but only days after I was able to get the Frankenbike Honda 350 back on its feet, I got a call from the owner who said, “ The bike got run over by a Toyota Tundra while it was parked at a cafe on Hwy 101.”

                                            Frankenbike revealed... on the way home again.

As if the owner hadn’t suffered enough trials and tribulations in the past few months, this happens! The only bright spot is that the perpetrator was kind enough to stay put, offer his insurance and driver’s license, and then paid $325 to have the bike hauled 30 miles down the coast to me on a Friday evening. If we can keep the costs down to around $1000, then the driver won’t put it on his insurance. So, we’ll see about that...

The bike arrived in the dark on a big roll-back tow truck. The tow truck driver had to back off the rear brake adjuster nut so he could roll the bike as the brake pedal was solidly jammed up against the footpeg bracket. I got up on the bed, holding the bike upright while the driver loosened the tie-down straps. He lowered the bed down to the driveway and I backward rolled the bike down to the ground safely.

I rolled it up next to my daily-driver CB77 and threw a cover over it for the night. On Saturday morning, the extent of the damage was revealed… The centerstand foot was twisted completely under the bike and the brake pedal smashed against the footpeg. The front wheel and headlight were all out of alignment. Sometimes you can loosen the forks and reset the wheel alignment, but in this case the fork bridge was broken at one side, so that put an end to any adjustment attempt. The bike is a 1972 CB350 and all of those twins have rubber-mounted handlebar mounts which are positioned into the fork bridge. This bike had none of that and it took about 15 minutes of research online to determine that the fork bridge and steering stem were from a CB400F! That model is in high demand for restorers, so spare parts are in short supply. After some digging, I found an eBay seller who had the bridge and stem for sale for $100, plus $20 shipping.

The next thing was to track down a brake pedal and centerstand for the bike, which were normal CB350 parts. There are a lot of these bikes being parted out, so I picked out the best-looking ones and bought the pair for a little over $100. Then you wait…

I couldn’t really tear down the front end, until the centerstand arrived, so all work ceased after I had removed the centerstand and brake pedal earlier in the morning.

When the parts started to roll in, I was able to install the replacement centerstand which has a powerful return spring. That allowed me to put a jack beneath the engine on a frame mount and push the front end up enough to remove the wheel assembly and eventually replace the frayed rubber boots with a new pair that came from an eBay seller. Finally, after using the front axle bolt as a guide to even up both fork assemblies in the triple clamps, I was able to get the front wheel pointed in the right direction again.

As a side task, I ordered a set of OEM Honda carb slide needles to replace the aftermarket kit parts which actually separated in the carburetor while running. I re-routed the cables and pinched the cable holder brackets together just enough to get the cable adjusters to stay put.

The brake pedal installation was the next to last task but took some time as the pedal that was purchased for the bike differed from the one that was removed. I wound up on the bench grinder whittling off some excess metal that was hitting the frame and engine cases. The part number changed from the original 286 to a 317 code part in the later years. Another case of assuming that most of those chassis parts were all the same through the years is when you find out the hard way that they are not!

Eventually, all the damaged parts were replaced, the carbs remounted with upgraded needles, and all the electrical systems working apart from the turn signals. The bike fired up on the second kick and made the usual racket from the poorly baffled mufflers, so I didn’t run it through the neighborhood at the 6pm finish time. The next day I was scheduled for a doctor's appointment about 2/3 the way back to Leucadia where the owner lives, so I loaded up the bike and hauled it back to it came from, prior to the accident.

In the end, it is still a Frankenbike with poorly designed modifications that will slowly fail in time. But for the owner, it is basic transportation that he sorely missed for the 10 days that it was with me being mended as good as possible, given the time constraints and the limited budget allowed.

I probably haven’t heard the end of this bike’s story, but for now it is functional and doing the best it can, all things considered.

Bill Silver aka MrHonda


Wednesday, November 16, 2022

Kiss my Keyster goodbye…. the Frankenbike 350 story continues

I have commented on the quality of the Keyster brand of motorcycle carburetor kits for years now, and am joined by many others who have suffered from the lack of accuracy of their components. I generally spend my repair time with 250-305 twins, but occasionally I have to work on bikes from a later vintage, often times 350 twins and an array of four-cylinder models. The challenge is that Keyster is one of the few remaining companies that make an attempt at offering repair kits for vintage motorcycles of all brands. 

You would think that a company that goes to the trouble of manufacturing carb components would have the expertise in duplicating the original parts accurately, but that is often not the case. We have found that the slide needles for the CB77 kits are too rich for Super Hawks, but work okay for Scramblers, which use a different needle taper. Likewise, all of their bowl gaskets are too wide where they fit into the forward slot in the carb base and don’t take into account that there are two little bumps that need clearance.

In recent years, the kits for the 305 Dreams started coming with #130 main jets which are way too rich for a stock bike that came with #120 main jets from the factory. Every time someone contacts me about difficulties with plug fouling on a Dream, the first question from me is: Does it have a Keyster kit installed with a #130 main jet? Often, lately, that is the answer to the problem. Early Honda models have JIS thread pitch jets, so you can’t plug in the later versions which are ISO pitch now. One of my suppliers does supply JIS main jets, separately from whole kits.

Usually, the plan is to reuse any OEM hardware pieces like jets and needles. I have discovered that the dimensions of the Keyster float valves are a little off, as well, causing the need to bend the float tang excessively to get the float height to be correct.

If you read my recent blog post

which was supposed to have been published back in September, you can see what kinds of problems can occur when you are using aftermarket components, like Keyster carb kits. Well, the story didn’t end there after all.

After a few days of happy driving, the bike became difficult to start and would stall out after a few seconds. I shared as much guidance as I could over text messages with the owner, but despite his best efforts the bike refused to come alive again. Part of the difficulty is that the bike is 30 miles away in Leucadia near my sister’s home. I only go up there about once a month for my nearby chiropractor’s appointment so I had hoped to be able to resolve the problems via text messaging. This was not the case, but my next appointment came due so I packed up tools and equipment to do a house call after my appointment.

Having tools on hand proved fortunate as my chiropractor needed some carb cleaning work on his Vespa Scooter, so I was able to trade services and save $125 for the visit. After that work, I drove down the road to the awaiting CB350 Frankenbike and its frustrated owner. Let the fun begin again….

Checking for battery voltage first, I measured 12.4v so that was a good starting point. The bike would try to start, then die as soon as the throttle was turned at all. There was backfiring going on during the startup attempt too, so that is generally an air leak or incorrect ignition timing. It was apparent that the right side cylinder was misfiring and not really catching on, so I focused on that side first. 

One of the other problems facing the owner was that the throttle cables wouldn’t synch up properly, which was eventually resolved after the carb cable extension to the left side had slipped out of the junction, leaving uneven lengths. The aftermarket cables have big fat junctions, unlike the originals, which can get trapped beneath the fuel tanks when the tank is set back on its mounts. The second problem was that either the threads in the carburetor cable holders were stripped or the cable end dimensions were undersized so that you can’t tighten the cable adjusters onto the carburetors. After a lot of fiddling, I got them as close as possible to matching each other and left it at that.

With the point cover off, the left side points didn’t seem to be opening very far which resulted in retarded ignition timing. The point adjustment was all the way open and the point backing plate was rotated as far as it could go but still, the timing was 20 degrees retarded, which explained the backfiring on that side. Eventually, I had to bend the point base contact outwards to get some point gap established and corrected the ignition timing. The bike started up and kept running but the right side wasn’t taking the throttle off idle, but it was idling okay. I thought perhaps the carb diaphragm was damaged, so removed the carburetor and pulled the top off to inspect the diaphragm. It looked fine but THE SLIDE NEEDLE WAS SEPARATED AGAIN! I don’t think that Honda’s Keihin carburetor slide needles are made in two pieces, but these certainly were. I tried to crimp the end of the needle slightly to make an interference fit with the little top hat end and tapped it back together again. It seems to be secure for the moment, but I don’t trust it at all now.

The bike started back up and was running on both sides, but idle mixture settings were off specs and there was still hard starting and some backfiring going on. I hit the intake manifolds with a blast of brake cleaner which I had brought along and the RPMs jumped instantly. A closer look at the manifolds revealed that the paper gaskets that were supposed to seal the manifolds to the head were blown out causing a huge air leak. The nearby Auto-Zone was a source for a tiny $6 tube of high temp RTV gasket sealer and the manifolds were glued back onto the cylinder head, solving that problem.

I had been on the job for more than 2 hours, improvising repairs and troubleshooting but finally had a functioning motorcycle, at least at the moment. I feel like starting a GoFundMe page for my suffering friend who still is sleeping in his car, next to the railroad tracks, living day to day from his meager income from photography work in the local area. He goes out and shoots local surfers in action, plus has other photography gigs in the county, but it isn’t enough to really get him settled into an apartment where the mean rent prices are in the $2k range. Surprisingly, he’s adapted to his situation the best he can for now, with a hopeful attitude for future work and a warm spot to call his own. See his work at 

I’ve done what I can do for the Frankenbike 350 for now. It needs a whole host of OEM parts to get its reliability improved, but it is what it is at the moment.

Bill Silver aka MrHonda


Frankenbike Honda 350 twin…

I received a desperate call from a man who needed some electrical work done on his “CB350” as his Prius had just died after spending $2500 on new batteries. Apparently, a cooling hose leaked out all the coolant on the freeway and fried the gas engine. I am not sure if he had already owned the bike or bought it as a temporary solution to his transportation needs. Unfortunately, the bike began to blow the main fuse, then with help from semi-knowledgeable friends wound up with a new, aftermarket wiring harness installed but not fully completed.

Day ONE--- Delivery

I didn’t ask all the right questions like, “Is it a stock CB350?” etc. so I agreed to have a look at it. After finally rounding up a friend and his pickup truck to haul it 35 miles down the coast, it arrived late on a Thursday… Arrgh! The bike was someone’s version of a “cafe bike” transformation, which still had the stock tank and frame, but the rest was non-stock, to say the least.

The fork tubes were shoved up in the triple clamps about 2” compressing the fork boots down. There were no fenders, front or rear. The stock seat pan was reupholstered and beneath it a tiny 4 amp battery was strapped down to the battery box. I was puzzled as to where the starter cable was hiding but then noticed that there was no electric starter on the front of the engine! It was an SL350 engine swapped into the CB chassis! The carbs were still the stock CB350 CV carb set, however.

The later SL350 engines have a special cylinder head with small ports and a pair of 24mm carburetors to enhance the low-speed torque and power for off-roading, but probably a complete mismatch for the 32mm CB carbs and their calibration. Oh, of course, there was set of noisy-looking aftermarket mufflers attached to the header pipes, which affects the carburetor calibrations, as well.

The “cafe” handlebars were the drop-down kind but all of the original length cables, normally on a set of much higher handlebars, were still in place looped around and around the front forks and handlebars. The clutch cable jutted out on the left side and was zip tied to a too-long spark plug wire, both hanging out in space. The owner brought a box of spares including another set of stock cables, which were useless on this application. There was a tiny aftermarket speedometer hooked up and a large H4 headlight mounted up front. The turn signals were tiny aftermarket units, as well. Pretty much anything that came from the factory was no longer present.

The fuel lines were that colored plastic stuff, that was then zip-tied to the fuel fittings. I had to drain the fuel tank through one of the fuel lines from the Chinese petcock which has reversed markings for the On-OFF-Reserve from normal. I barely got one of the lines off, but the back one pulled the fuel fitting out of the petcock body. I hate this stuff!

Looking over the electrical connections, it appeared that the condensers and coil wiring was incorrect, but all of the wiring colors are different on the aftermarket harnesses, so a 12 v test light will get a workout as I sort through the connections. An aftermarket rectifier-regulator was installed but the wiring colors don’t seem to match up.

I went online and quickly ordered a set of short cables from along with 5 feet of 5.5mm Honda fuel line, with payment for 2-day delivery which cost $37!

Day TWO- Investigation.

I had a leftover Li-Ion battery that was larger than the one in the bike and might work out better for this bike. Even though it showed fully charged after a few hours, the Li-Ion battery failed the self-test, so the little 4 amp battery was charged overnight and reinstalled. Then the fun began…

Turning the ignition switch to ON blew the 15amp fuse. Looking over the wiring to the points and condenser, it appeared to be miswired, so after reconnecting the condenser, coils and points, the switch was turned ON again… and another blown fuse. I did an ohm test on each coil and the left side which was a made-in-China Tec coil had shorted out to .6 ohms. The opposite coil was about 3.8 ohms. In the box, of spare bits was another coil, which tested out okay and when installed the fuse stayed intact. One small step towards success. Unfortunately, the replacement wiring harness had wire colors unknown to Honda’s engineers, so it took time and getting a copy of the revised wiring harness from to help guide me through the process, one wire at a time.

Using a 12v test light, I was able to probe various wires for power or ground and eventually got everything that was supposed to be connected… connected! Power ON showed headlight (both beams), tail and brake light functions, ignition power to the points and power to the rectifier/regulator. I tried to kickstart the bike, but it didn’t give any signs of wanting to run. Compression checks revealed about 150 psi on each side, but the engine sounded noisy when kicking it over.

Putting a wrench on the rotor and turning the engine forward/reverse demonstrated some slack in the camchain, which was reduced with a camchain tensioner adjustment. The tappet covers were almost unmoveable except for my adjustable Sears 6 point 12” long wrench which finally broke them loose without breaking anything. As suspected the tappet clearances were WAY off. I noticed that the little index marks for the ends of the rocker arm adjusters were not all in the usual 4 and 8 o’clock positions, so that was all reset.

Next step was to tear the 722A carbs off and see how they were doing inside. The first thing was that there was a lot of unmarked parts indicating some off-brake carb kit installation. The float levels were in the 19-21mm settings, which is fine for early carbs but doesn’t match the 26mm suggested settings from Honda. After the floats were reset, the carb tops were removed to check the condition of the slide diaphragms. The left side had the usual little locating tab, but the right side did not. When the slide was inspected the non-adjustable needle had separated and the top was left inside the slide body, while the rest of the needle was sitting in the needle jet inside the carb throat. I didn’t realize that these needles were made in 2 pieces! I tapped the top back on the needle portion and hoped for the best.

When the right side carb was inspected, it had an incorrect float level setting as noted above, with a non-indexed diaphragm. The needle was also dislodged, but not separated. Whoever put the needle back into the slide didn’t secure the wire clip that holds everything down in place, so that needle was jumping around too. The owner said that the bike had been running previously, but not well. Duh! I am surprised that it ran at all. With carbs done, I awaited the new short cable set from to come so I could install the new throttle cable, along with the clutch and front brake cables of a more appropriate length.

Day THREE… updates

The Priority Express mailing of the cables failed to arrive in the 2-day period. Ordered on Friday, they finally landed on Monday, which normally the regular Priority Mail shipping ($15) would have sufficed. contacted USPS and actually got a refund for failed 2-day delivery. The old cables were already disconnected at the handlebars, but not without more difficulties. The cable adjusters were somewhat corroded into the lever mounts and the ends of the cables were corroded as well. Prying them apart finally released the cable ends and the adjusters went into some Metal Rescue for de-rusting. With non-standard handlebars, the best cable routing has to be determined by trying various routes to allow the cables to move properly and not be pinched by the fuel tank. The clutch cable goes into the left side cover where it connects to the clutch lifter hardware. Finding the right path took a few tries, but eventually raising the handlebar angles helped make it all fit.

The bike was fired up, finally, with way too loud mufflers blasting my quiet neighborhood. The bike ran unevenly but finally went down the road under its own power. Kickstarting was kind of random when the key was turned on, eventually, that problem was traced to an erratic aftermarket ignition switch function. I finally had to “test” the switch with the horn button to see if it actually had turned ON or not. I dismantled the switch and smoothed out the contact plate, but it still seemed to have some dysfunctional moments.

Day FOUR… too much drama

I told the owner that I thought the bike was ready to ride after about 6 hours of labor and adjustments of the engine and fuel system. I also had to seal up the leading top edge of the fuel tank with some tank sealer as there was a fuel leak right at the seam. The owner had to come down to Spring Valley on the Coaster train and then on a bus to my neighborhood. I had just returned from appointments, so the timing was about right. He appreciated all the work that I had done and wanted to add value to the transaction by shooting some photos of me and my NT650 in action and in some scenic spots nearby.

We rode out to Mt. Helix which is a panoramic viewpoint in the La Mesa area. The bike seemed to run okay as he trailed me on the Hawk GT. We took some photos around the top, then when we went to leave the bike wouldn’t start back up. It appeared like the left coil wasn’t firing again and it just wouldn’t light up on the right side. I rode back home, got my Tacoma, and returned to load up the 350 and bring it back home for diagnosis.

It appeared like the left side coil still wasn’t firing properly. I replaced it with another spare from the extras in his parts box. The bike started up and I drove it over to the 7-11 to fill up the tank for the journey home. The bike started dropping one cylinder again, but this time it was the right side! I would not fire up again, so the owner was summoned to bring my truck over, and pick me up so I could return home and get the ramp and tie-downs again. We were only about ¼ mile from home, but we were losing light and the owner had been planning to make a coastal journey back home which was looking less and less likely.

Troubleshooting the bike, I finally tested the battery voltage which had dropped to 8 volts with key OFF and 5 with key ON. Okay, a combination of a failed charging system and perhaps an undersized battery were the current causes of failure to keep the bike alive. I wound up taking my owner friend back to the train station in downtown San Diego, which is a 14-mile drive, one-way, and promised to get to the bottom of this problem the next day. I had to take responsibility for the fact that I never checked the charging system output during all of the running and electrical repair work.

Day FIVE… Battery hunting

Calling the local Honda dealership, it seems that the correct battery for an electric start CB350 was NLA at any of the other motorcycle dealers in the SD region! I called Interstate battery and they said the battery was back-ordered. I finally found a battery store out in Santee (12 miles away), that had two in stock! I made the trek out to the store and secured the new battery, turning in the old 4 amp battery and the leftover Li-Ion spare as well.

Dropping the already-charged battery into the bike, I noticed that the static voltage was about 12.5. With the key ON, it dropped to 12.25, which is pretty normal. The bike sputtered back to life again now with full voltage to the coils and cleared off some of the unburnt fuel in the cylinders and on the plug tips. Revving the engine up, the voltage failed to increase, so there was more hunting to do.

I had to remove the left carburetor, which is easy with no air filter box to have to remove. This gave me access to the electrical plug that connects the stator windings to the main wiring harness. Pulling the plug apart, revealed that two of the female connector pins had pushed out of the connector, thus no AC power going to the reg/rectifier. Finally, the last smoking gun had been discovered. Reassembled again, the voltage increased to nearly 13 volts with no lights on and held steady around 12.5 with the lights back ON again. Another run down my test circuit was successful with the engine pulling towards redline and running well on both sides. Repairs finally completed… or not!

The engine was drooling oil down from the dyno cover side gasket. From the appearances, I would guess that someone made a gasket to fit, as most CB350 gasket kits would have supplied a dyno cover gasket that incorporated the electric starter function which this bike did not have. Digging through a pile of misc gasket sets, I discovered what appeared to be the correct gasket. That will be a job for the next day.


To prevent oil loss, the bike was leaned up against a wall so the dyno cover gasket could be changed out. The rear engine cover needs to be removed first, but that only happens after the shift lever is removed, the footpeg bolts loosened up, and then the cover was

removed. The gasket replacement was successful and the bike was sent back home for local transportation needs. I can only hope that it continues to function given the difficulties that were presented with this Frankenbike 350.
Factory AHMC photo of what the bike looked like originally

Bill Silver aka MrHonda

Sept 2022