The powdercoating work was completed the same day as a recent pre-Ortho appt in the same part of town, so both tasks were combined with success. As the bike parts were aged and rusted/corroded, it is unclear as to what the final finish will look like until it’s done. The color seems really close to Honda’s Cloud Silver in tone, so the CL72 parts may head down that path in the future, just to brighten up the overall look of that bike.
Once un-wrapped the bike parts were sorted and the frame laid down on a big blanket for initial assembly. Before you can begin, there is an inspection process to determine of powdercoating has seeped into places where you don’t want it to go. Additionally, there are places where the chassis grounds need to be reestablished for electrical continuity. The tail light bracket needs to be grounded to the tail light assembly and the rear fender. The rear fender needs to be grounded to the frame, as does the engine assembly. If the fork covers are not cleared to metal in a few spots the headlight won’t work due to lack of electrical continuity.
Once the frame is cleaned and inspected for assembly issues, then work can continue in earnest. The steering head bearing races must be driven back into the frame and the lower stem race/washer/dust seal reassembled. This is followed by the joy of packing grease carefully in the bearing races to allow the 37 ball bearings to be set in place. Once the stem is inserted into the frame’s steering head, the stem nut can be spun down to secure all the bearings in place. If the races are not fully squared up in the frame or not fully driven into place, the steering head bearings will loosen quickly, causing handling issues.
With the steering stem in place, the frame can be inverted to allow for placement of the centerstand and swing arm. This bike came equipped with the optional sidestand, but the correct lengthened centerstand pivot bolt was not used. The end of the bolt needs to extend past the thicknesses of the frame and centerstand bracket plate, in order to secure it with a lock washer and nut. The standard length bolt isn’t long enough to accomplish the task correctly.
The swing arm pivot bushings and collars must be lubed and driven back into place once the holes are cleared of any powdercoating. New dust seals go onto the frame lugs before the swing arm is installed and the long pivot bolt inserted and secured. The swing arm bolt must be inserted from the right side of the bike; otherwise the grease fitting on the end of the bolt fouls the right side footpeg bracket.
When working in “low budget” mode, all the hardware requires individual inspection and generally a round on the bench grinder’s fine wire wheel end. Other de-rusting options are the use of phosphoric acid (metal prep) on both steel parts and to dissolve the scale left on non-ferrous parts like carburetor bodies and float bowls which have encountered water contact in the past. You have to keep an eye on the parts as they will darken considerably if left in the solution too long. Fresh water neutralizes the acid and then a good squirt of WD-40 or similar products will prevent immediate rust formation on the newly exposed steel surfaces.
While all the parts and pieces were being checked, cleaned and installed, the fuel tank had been filled with 3 gallons of apple cider vinegar, plus water to top it up. The fuel tank had been powdercoated in as-is condition with quite a bit of rust formation inside. A trip through the 450 degree oven at the powdercoating shop burns off any loose varnish/gasoline deposits usually leaving a fine powder of rust particles inside the tank. After a shake/blow out with compressed air, the tank fittings were sealed up and given the apple cider treatment for a few days. While not as rapid-acting as phosphoric acid, it DOES do the job of dissolving rust particles and surface formations. The tank will be drained, flushed out with clear water and air-dried as rapidly as possible, before the final tank coating treatment is applied.
Once the suspension systems are mounted up, the rear fender and wheels can be installed and you have a “roller” once again. To install the rebuilt 305cc engine, a small portable bike lift has been the favored way of moving the engine from the bench to the lift and then lowered for transit to the chassis. The CB77 engine needs to be installed pretty much straight up and back into the frame. Once the first couple of bolts holes are exposed, long screwdrivers can be used to help secure the weight in place, while some final jockeying takes place to insert all six of the engine mounting bolts. It is beginning to look more like a motorcycle now with the engine installed, but there is a lot more work to do after that.
The original wiring harness was pretty tatty and hacked up, so a replacement 268-305 code universal harness was selected as a replacement. This harness is used around the world for bikes which are equipped with turn signals, which were not required in the US models. The US bikes had a “wires deleted” harness with the “ YB72” part number, indicating that the harness was an “accessory” listed part. The harness works on all applications, but you wind up with extra unused wires, if turn signals are not to be used for the rebuild. This bike came with some awful add-on turn signals and additional handlebar switch and flasher unit to complete the installation. All the wiring was done outside of the harness as the bike was not wired for those “winkers” from the factory. On top of that a relay and dual horns were mounted up front on a fabricated bracket, so more loose wires were floating around the chassis.
The final electrical parts challenge was that the ignition coils, which were that odd green color seen on early bikes, were rusted and all the wiring was damaged. Thankfully, my good friend Scott, whose parts bins have been raided for the past few years, happened to have a set of NOS CB77 coils remaining in a shop drawer. We worked out a cash/labor swap and the coils were mine. Once mounted on the chassis, the final steps towards fire-up and completion were drawing near.