Tuesday, December 19, 2023

L’Orange CB77 from 1963 +1… Part 2

And the beat goes on….

I was called by the owner, described above, in early Dec. to see if I could help him with repairs to the CB77. He had sold both the 1963 CB77 and a 1966 CL77 to the same owner in nearby Rancho Santa Fe. He sent photos of a large pool of oil beneath the CB77 and maybe a little leak beneath the CL77. The new owner was requesting assistance in getting the oil leaks repaired as soon as possible.

I was going to be in the general location (about 40 miles from home) for my monthly chiropractor visit, so it was convenient to swing by and have a look. It wasn’t pretty….

I had never seen that kind of oil leak beneath any 250-305 before, unless the drain plug was loose and the bike sitting for weeks. I had brought tools and the previous owner supplied some oil seal kits so I could hopefully do an on-site repair and head on home. After a quick view, it was obvious that the bikes needed to come back home with me for repairs. The new owner had left the key in the PARK position, so the battery was completely dead. 

The oil leak was drooling from the shift shaft seal, which is an easy replacement, but the oil smelled of gasoline which apparently leaked into the crankcase before the last ride. Somehow, the gas-oil mixture didn’t ignite when the bike was operated and then shut down. The diluted oil leaked past what was probably the original 60-year-old seal and drained the crankcase down to where the level was nearly at the seal level in the clutch cover. Thus the large pool of oil beneath the bike.

Both bikes were loaded up into the Tacoma and hauled back to Rancho de Honda for repairs. The next day I changed out the shift shaft seal, then drained the oil as the drain plug appeared not to have a gasket installed. What drained out was watery, dark-colored oil that reeked of gasoline. I had also replaced the crankshaft seal and was putting things back together when I turned the engine over with a wrench and heard a god-awful squealing sound emanating from the engine somewhere up high. It was one of those fingernails on the chalkboard kinds of noises, which got louder when the spark plugs were removed. My best guess was that the diluted oil had caused some kind of metal-to-metal damage and that the engine would need to be removed for inspection and repairs. After the findings were relayed to the owner, permission was granted to move on to the repairs.

I did pull the clutch cover off, just in case the primary chain nut was backing off or something else was loose under the cover. I did find the oil filter was tight on the shaft and that the outer clutch pressure plate was contacting the inside of the clutch cover, too. The filter needed servicing anyway. Clearance was provided so it spun easily on the shaft as normal.

Once the engine was out, the top cover was removed and the crankshaft was turned again to try to pinpoint the squealing noises. The top end looked pretty dry, but nothing horrible stood out. I shot some WD40 into the cam bearings, where I thought the noise might be coming from, but it didn’t have any effect.

The cylinder head was then removed and the noise became centered on the pistons and rings. The cylinder walls were dry and the rings were dragging against the cylinder walls metal-to-metal. I suppose that if I had just shot some oil down the spark plug holes when it was still assembled, the noise would have been reduced and that would have pinpointed the cause of the noises. Still, there was evidence of the head gasket leaking up front and around the edges, so it was best to just go through the top end anyway.

The speedometer was showing less than 9k miles and the relative lack of carbon buildup on the piston crowns and valves seemed to reinforce the truth of the miles shown. The ring gaps were not terribly excessive, but the to edges of the rings were worn sharp and several of the rings were sticking in the ring lands of the pistons. The pistons were free to swing back and forth on the rod ends, but the piston pins, themselves were immobile when the clips were removed. Again, I give thanks for finding the Benelli piston pin removal tool that I had bought a few years back when I owned a Benelli Sei. Using the tool to its fullest the pins begrudgingly gave way to the tool’s force and were removed. One pin had an odd wear spot on the middle of the pin, but mostly they were undamaged. Piston pin fit is normally a finger push fit into the piston pin bores, so it is unclear why these had become so tight. I have a bottle brush hone that is the right side to open up the pin bore holes and it was used to allow a proper pin fit.

I had the cylinders honed at my local machine shop and ordered new STD piston rings from who turned out to be a former San Diego friend who moved to Minnesota a few years ago. While waiting for the parts, I disassembled the cylinder head, checked for any damage, touched up the exhaust valve seats, and reassembled it all.

When I turned to the round bowl carburetors, I discovered that someone had sealed up the overflow tube on one float bowl and that the main jets were #125 instead of #135 specified. The float levels were set at 26mm instead of 22.5mm so perhaps the bike had lived in high altitude for part of its life. The carb insulators were RTV glued onto the carburetor flanges and cylinder head. The more you look the more things wrong you find, in many projects like this.

The float bowl overflow tube had a split down the side causing a fuel leak, which was soldered for repair. The floats were original round bowl types, which come close to the side walls of the float bowl. I had many leftover round bowl gaskets from kits which contained both round and square bowl gaskets. Sadly, most of them had come from Keyster kits and they are just not made correctly to OEM specs. When the bowls were removed, the gaskets were cork and had shrunk up quite a bit. I ordered new floats from 4int1.com along with their swell-proof gaskets.

I had already removed the clutch cover, so I thought I better check the clutch plates. They were, of course previously stuck and there was rust embedded into the steel plates. Oddly, the outer pressure plate edges were sticking up proud of the edges of the clutch basket, instead of just tucked under the edges. This stack height apparently led to the contact marks inside the clutch cover. All the plates seemed to be of the right thickness and number (it was a 6-plate clutch), so I decided to mix-match the clutch pack with some thicker 268-020 plates, just fewer of them. In the end, it was a little shorter than normal, but it will clear the clutch cover now. We’ll see how that works out in the end…

I cleaned the carb insulators of the black RTV that was coated over them and installed new Honda 260 code o-rings on the insulators and the carburetor flanges. The cleaning process always involves flattening out the flanges, changing the o-rings, and checking for any tendencies for the slides to stick in the carb body bores. The main jets will be bumped up to #140s, which seem to work better on today’s E10 gasoline, which causes engines to run lean on standard settings.

When the engine was installed, I tried to quick-fire it up, but it backfired and spit back. The coils were tightly grouped together and the leads crossed each other. Swapping them back got an initial startup, but the ignition timing was incorrect. When the right side points were adjusted, one of the point screws was stripped in the hole, so a substitute point plate was acquired and installed. After picking up a fresh set of D8HA NGK plugs and raising the needles up a notch, the bike finally fired up and settled down to an idle. The throttle cable was a bit cranky and the cable adjuster on the right side carb is raised up more than the left to get them synchronized.

The last step will be to replace the old floats with the square bowl types that have more clearance around the edges, so they don’t interfere with the float bowl gaskets. Of course, the petcock needed to be rebuilt including the brass tube that was down to about an inch high.

On top of it all, the tires are old and the drive chain needed to be replaced. I did find an inexpensive new 530 pitch drive chain and installed it before placing the kickstarter cover back on the engine. Setting the clutch adjuster with the new clutch pack setup actually caused the alignment marks to be just about right. The tire pressures were 18/12 psi when I took it around the block, very slowly.

The co-conspirator….1966 CL77

This bike came down with the 1963 CB77 for a checkover and a small oil leak complaint. It was parked next to the CB77 in the garage, adjacent to the large pool of oil/gas on the floor. I had gone through the bike earlier in the year after it had been sitting for about 10 years. It required the usual fuel system clean-out, a new battery and, and overall tune-up procedures.

I had ordered a pair of the pushrod seal retainer kits from the Cappellini dealer on eBay. The first one went on the CB77 after the extensive rebuild. This second one should have been a 15-minute parts swap but turned into over an hour due to discoveries beneath the kickstarter cover.

First, the two 6mm counter shaft plate screws came out very hard, perhaps installed with Loc-Tite. After I removed the screws, I wanted to clean up the threads for the new retainer screws. The 6mm tap went in about half-way on both sides, then sheared off when I was trying to get that little bit of extra thread clean-up. There’s no getting broken off taps out of a hole like this, apart from an EDM machine. Fortunately, I had a spare shallow spline sprocket that was in decent shape. So, that problem was solved. HOWEVER….

When the sprocket was pulled from the countershaft, I was amazed and horrified to see that the countershaft seal was partially hanging out with a large open gap between the engine case and the edge of the seal. It had been installed with some of the Permatex Moto-Seal or Honda-bond liquid sealer when the engine cases were bolted back together again. Whoever did it, failed to notice that the seal had squeezed out at an angle and was left in that condition. Not only that, behind the rotor there was JB Weld, right where the engine cases get damaged from failing to locate the crankshaft main bearing in the knock pin correctly.

It’s hard to know if the damage was done before the last engine work or during the assembly of it. The possibilities are that the bearing was reset and the oil hole was not blocked. The other scenario is that the bearing was left in the out-of-indexed location, which blocks the oil flow to the crankshaft bearing. The builder might have noticed the cracked engine case and just sealed it up, rather than dive back in to reset the bearing properly.

The bike has straight CL72 exhaust pipes with the Snuff-or-Nots installed at the back. They knock down the noise a little bit but I’m sure that the neighbors would prefer that I not run the bike around for long. The bike repair work was done, but was waiting for the return of the speedometer repairs from Foreign Speedo in San Diego, my go-to guy for vintage Honda speedometer repairs.

When the bike was ridden the speedometer needle was whipping around and scratched the faceplate. Fortunately, Foreign Speedo has a guy in San Diego who can silk-screen the faces back to their original condition, so there is a time lag when he comes to pick up various faceplates and when they are returned. The bike runs out very strong (and loud), so the speedometer is all that is needed to return it to service.

The bikes are scheduled to be returned on Dec. 28 in much better condition than when they left the owner's garage. 

Just another few weeks in the life of MrHonda...

Bill Silver


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