Hi folks. I'm in the process of rebuilding a 1966 CB77, and I just finished the teardown of the motor. I am fully expecting to replace the 'common wear' parts mentioned in most of the rebuild threads and FAQs, but I have some specific questions regarding the shift forks and the gears they mate with. I'll include pictures at the bottom of this post, rather than intermix them with the text.
One of the shift forks is obviously toast, but the other only has a little wear at a few points. This isn't a high-dollar project, so if I can reuse at least one of them, it would be nice (but not worth any risk if it's a questionable choice). More than that, however, I'm curious about what causes this type of wear in the first place, and whether or not it necessitates replacing the gears as well.
I can't imagine this much wear can occur on the forks without some kind of damage to the gears, but what little I can tell with my naked eyes (which arguably isn't much) seems to indicate nothing that would make them unserviceable. Right now the gears are in a tub of motor oil to prevent any flash-rust, so I wasn't able to take any pictures (though I will sooner or later). I just thought I'd first see if it was common to replace the forks as well as the gears as a package deal, or if there was any kind of specifications for properly inspecting them.
Any advice would be appreciated tremendously. Thanks!
(Sorry for the dodgy pictures, camera is a 6 year old point-and-shoot...)
[Edit - I removed the terribly huge externally hosted pictures and re-uploaded using the attachment tool. Sorry about the mess.]
CB77 Shift forks and gears - salvageable? (High res pics)If pic 4 & 6 are the same fork, I'd guess it would be okay. If the tips aren't groove you should be all right.
The other pictures show some wear. My guess is it was either missing 2nd gear or would be soon. That seems to be a common wear area. I'd check for galling in the groove of the gear where the fork rides. My second gear even had a hairline crack. A good used fork and some offset cotters can make the tranny last a lot longer. 63 CA78
Thanks for the response OldStan, much appreciated!
Pictures 4&6 are indeed the same fork, and there's only the tiniest bit of wear at the 3 discolored spots in picture 4 (not even enough wear to catch my thumbnail). Is there any way to recondition the other fork and the gear it mated with if galling is indeed a problem? Also, you mentioned offset cotters, but I can't find much information on these. Is it an aftermarket part? I tried a forum search, but I couldn't find anything beyond a few passing mentions. I do recall during my disassembly that one pair of cotter halves seemed offset while the other pair did not (perhaps the offset pair was responsible for the less worn fork?). Is this swap simply getting another pair of offset cotter halves and having them installed on both gears? Thanks again! I suppose you could weld the fork with hard facing and precision grind it back to thickness, but I haven't tried, I'm not equipped for that. If the groove is not too badly galled you might be able to take off the high spots with a file, but you really want a smooth surface. Your best bet for longevity is NOS or good used parts. The cotters are a Honda part. Beside the standard there are two different offsets. You don't just install an offset, you have to test fit it for gear engagement, and clearance in neutral. Remember moving it for more engagement in one gear means less engagement when shifted to the gear in the other direction. 63 CA78
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