After a harrowing journey across the US (New Hampshire to San Diego) in the middle of winter, two rare CB92s arrived at 9PM on a Friday night. It was a 10-day trip, zigzagging across the NE before a swing down to Louisiana, then across the southern route through Texas, New Mexico, with a stop in Phoenix and finally back down to San Diego. They seemed to have arrived basically unscathed, apart from a cracked windscreen that looked fresh and a broken damper knob. Neither bike came with a key, so that will take some research to solve.
The rundown on the two machines looks like this:
1960 CB92 with a CA assigned engine number sticker on the left cover due to apparently replaced engine cases of unknown vintage. The top case is blank, so obviously a replacement. The replacement upper case does have the “rear breather” system used on the 1960 models, so that part is still correct. After trying to refit the megaphones, it became apparent that the bottom engine case was from a standard Benly model, due to the extra lugs cast into the cases, just behind the forward muffler mount points. The fix for that was to saw off the lugs to make it match the standard CB92 case set.
The frame number is located up on the steering head on the 1960 bikes, then moved to the obscure and hard to find location on the left rear of the frame after that. This one is serial number CB92-010787. The bike has alloy DID rims, front brake vented air cap, a racing seat and a factory megaphone exhaust system. A peek beneath the tappet covers revealed YB alloy racing valve spring retainers. The 20mm carburetor is marked CA95, which is the same size used on the later CB92s. The original carburetor size was just 18mm.
It arrived without the headlight shell in place, but that whole assembly (speedometer reading 951 miles) came in a separate box, along with the original rear mudflap in blue and windscreen/brackets. There is safety wire on various areas of the engine, as if it was being prepped for roadracing duties. The kickstarter arm and shaft are missing, but the stock starter motor is still in place. The original fixed footpegs were sawn off and replaced with fold-up versions. A “YB” racing tachometer, which was affixed to the 1961 bike’s headlight shell, as been removed and allocated to the 1960 bike, as it is running many of the YB parts and seemed destined for racing duties. The factory tool kit is almost complete with tools that are marked Sanki, not Kowa, but have the HM logo on the back sides of the big wrenches.
1961 CB92 carries a CB92-1101150 frame number with a CB92E-1101122 engine number. The speedometer reads 3142 miles. This model has a steel fuel tank and side covers, but retains the alloy front fender and rear shock cover trim pieces. The MSO paperwork from AHMC shows the bike to be a “CB92R” edition; however it has standard steel wheel rims, nice OEM seamless mufflers and a stock blue seat. Unfortunately, someone modified the swing arm to mount up some passenger pegs, which damages the stamped steel sheet metal construction. The engine turns through okay with unknown compression readings and has both the kickstarter arm and the electric starter in place. The tail light on this machine is the 253 code version with the rounded edges (vs. 255 with rectangular shaped lens).
The bikes don’t have keys for the ignition switches, although there is a NA series key which fits and can be re-cut for the 1960 machine, as well as a key blank for the tire pump on the 1961 model. The 1961 bike has a 3 digit key code with no letter designators.
There are two new batteries all serviced up and nearly complete OEM gasket kits for the engines. Some of the wiring connections need to be repaired/replaced, but main harnesses seem to be intact and correct. The left side cover tool tray was missing, but one was sourced from eBay and installed to help anchor the alloy cover, which has had some trimming done to the forward edges; perhaps as a way to increase air flow to the carburetor through the frame.
The 1961 bike has the original Mitsubishi branded tires on the steel rims, while the 1960 bike has some Bridgestone street tires spooned onto the alloy D.I.D logo-stamped rims. Both bikes are “project” machines, but certainly worthy of restoration in their respective forms. Only about 1,000 CB92s were shipped to the US from a total production of over 25,000 worldwide. At only 125cc, they were high-performance “learner” bikes in many countries and the “Baby Boomers” who learned to drive on a CB92 seek them out once again. Over the years, there have been many shared stories about these machines being used and abused during their day, often with disastrous outcomes. Despite the capability of nearly an 80 mph top speed, they were rather high-strung and subject to either piston seizures or dropping a valve after prolonged road work.
Honda redesigned the crankshaft at least three times, requiring engine case changes for each edition. On the early 1960 models, the left side cylinder was “windowed” to all some additional oil to lubricate the piston skirt. A thin channel was machined from the base of the cylinder block across the back to the hole opened up in the bottom of the cylinder sleeve. The original oil pump, which is located on the right side of the engine, was upgraded to a larger piston to increase lubrication all around, but with only a one quart oil capacity any loss of oil, due to consumption, put the engines right on the edge of failure.
Fitted out with the accessory “YB” racing parts, these bikes were formidable weapons on a race track. The racing megaphones are some of the loudest exhaust systems imaginable and with the optional racing cam and piston combination, something beyond 16 horsepower was available to propel these 250 lb beauties down the track. Graced with 200mm (nearly 8”) brake drums, with the front being DLS actuated, the bikes were really only hampered by the archaic leading-link front suspension and jack-hammer rear shocks with little damping on either end. Compared to just about any other 125cc machine being offered in the early 1960s, they were a revelation of design and pure function.
Racers, who are never content to leave things alone, tried more tricks to improve performance. The YB pistons so crowded the combustion chambers that side-gap spark plugs were needed to clear the piston crowns at TDC. Even wilder camshafts were tried, coupled with improved valves, valve springs and the alloy valve retainers, which were lifted from the Honda C110 racing kit parts. Honda’s bag of tricks included the high performance “red-wire” ignition coils which were fired from the crankshaft-mounted ignition points. The lists of performance parts for these models was quite impressive and most were very effective in helping Honda achieve great results at the track.