It’s hard to know just where to begin when you tackle a revival job like the one that the 1963 CB77 has presented this month. Rattle-can spray paint all over the frame, footpeg brackets, on the sidestand bar, the rear brake backing plate, the starter motor and front of engine makes for lots of deep cleaning exercises. A trip to Home Depot yielded a gallon can of paint stripper gel with a handy spray bottle applicator. A half dozen over-sprayed parts were selected and laid out on an old towel to receive the gel treatment. The can stated a 15 minute effective loosening time, so the parts were sprayed and left while other issues were dealt with on the bike.
The grimy engine cases, cylinder, cylinder head, clutch cover, top cover and other smaller pieces were dropped off at the local auto engine rebuilder shop for a long soak to degrease the parts, leaving just the leftover scale on the aluminum parts. The scale can be dealt with by using phosphoric acid and a brush to dissolve the scale, followed by a quick rinse-off with water.
If the crankshaft can be cleaned up on the one crank-throw weight which has some extensive rust, the bearings will have to be replaced anyway, as rust had worked its way into just about all the ball bearings inside the engine. Because of the low original miles on the bike, little actual wear was noted. When the clutch pack was removed, it proved to be an early edition from the Barnett Company. The plates were all heavily stuck together, so the whole clutch pack will have to be discarded.
The camshaft and rocker arms are all quite good, but the cam bearings were all rusted so will require replacement. There was some rust in the left cylinder head combustion chamber, where the stuck piston was located, but when the valves were all taken out of the head, they cleaned up nicely with a brief run on the wire wheel. A newly acquired set of OEM valve seat cutters will be pressed into service when the head returns from the hot tank bath.
The spares box yielded a good used early-style crankshaft and a set of later model die-cast cylinders already bored to .75 over. A spare NOS head with valves is available, but it is the later version with V shaped forward fin pattern and has no air passages drilled, which gives it a 1967 application.
More digging turned up a new camchain tensioner, primary chain tensioner roller arm and a full lower end repair kit setup of low gear bushing, offset cotters for the transmission, locking washer for the crankshaft nut and new special washer/nut for the bottom case.
An hour was spent on the brake plates; driving out the old stuck brake cams, scrubbing everything clean again and lubing the cams for reinstallation. There were signs that the front brake shoes were not fully bedded-in at the 5k mile reading on the speedometer. Again, there is little wear on most of the machine’s parts, just a lot of faded paint, rust and corrosion of the alloy parts.
The engine cases were sent off to the local automotive engine rebuilder shop which has done this degreasing service in the past. When the call came in to pick them up again, the result was rather shocking in that the cases had taken on a brown-ish tint and the remaining scale needed brisk brushing with brass bristle brushes to get down to the parent metal. After further washing with Simple-Green and another round of phosphoric acid, little had changed in the way of the external appearances. Reluctantly, the cases were taken to NC Motorcycle for a turn in their blast cabinet. Unfortunately, the blast cabinet was in need of some repairs and new media so the cases were left at the shop for a few days.
The frame required welding and fabrication of the back section of the battery box where the rear fender tab anchors the front of the rear fender to the chassis. Battery acid had eaten its way through the metal so the rear fender no longer had a stable anchor point. Additionally, the tool box tab spot welds were letting go and needed to be welded back down in place. A little metal work is needed on the front edge of the front fender and the chain guard seemed to have taken a hit when the bike tipped over once, so the metal needs a bit of straightening. Fortunately, my good friend Rob North has recently recovered from a serious illness and has just returned to his workshop. He offered to take in the small repair work tasks so the chassis can be shipped off to the powdercoaters for refinishing.
Even without doing a complete restoration, the costs and time required to clean, inspect and refinish or replace every part of the motorcycle can become a daunting task. The current plan for this particular machine is to be revised from the faded, orange-ish Scarlet Red original color to a mono-chrome Silver finish for the entire machine. Honda did create a limited number of all-chrome plated CB77s during several different years of CB77 production, so this may mimic that effect, while forgoing the massive chrome-plating bill.
In the meantime, the engine was scrubbed numerous times with Simple-Green and then phosphoric acid more than once. A final trip to a local m/c shop netted some bead-blasting time to help smooth the cases and clutch cover, which were then painted with Duplicolor’s Cast Aluminum engine paint. All the engine internals were inspected and most tossed aside for good used parts in stock. The crankshaft rod end on the left side had a loose pin bore fit, so an o/s pin was installed after extensive honing of the rod. The hole was somewhat oval shaped, so despite a snug pin fit going across, there is some rocking wiggle on the horizontal plane. The piston should minimize the pin rocking, but it is a 50/50 deal at this point. The original crankshaft had some rust build-up on the crankwheels and bearings sufficient to set it aside for now.
The top end has .75 over pistons/rings in a late model, narrow-tensioner die-cast cylinder block. The late version cylinder head has new valves, but no intake valve venting passages, which were deleted at the factory in 1967. The cams and rockers were reused, but new cam bearings were installed. The camsprocket seemed to be in decent shape, so was reused when the new camchain and guide roller were fitted.
The powdercoating is due any time and then the chassis reassembly can begin in earnest. So many parts and so little time left before Bill goes under the knife again for another total knee replacement! Stay tuned for the big reveal…