Motorcycle Repair/Honda 350 cam question follow-up
Hi, Bill. This is a follow-up to a question I asked a while back about a loud vibrating noise to my CL350 ('71 motor). Finally got some time to yank the engine and discovered that the "rebuilt engine" (which really did look rebuilt with new gaskets and no carbon on the valves or piston tops) had either a stretched or overly long cam chain that was slack enough it had been slapping against the walls of the head. Seemed to be a couple links too long (I don't know for sure because after removal, a dumpster diver promptly stole it from the carport where I had laid it aside), and I assume that was causing my rumble/vibrating sound. OK, so we ground it apart, wired on an open Tsubaki, pulled it through the engine, and prepared to link it together as a replacement chain.
Sounds simple, right? Well...we did that and discovered that the Tsubaki is a link or two too short! If we force it up into position for linking, the chain is so tight that the tensioner will not retreat back into the case. So I shook my head, concluded there is some problem with the Tsusbaki, and ordered a stock 94 link cam chain. Chain gets here and I repeat the process with the same results: While everything I can find indicates this bike (and all cb/cl 350s) takes a 94 link cam chain, a 94 link chain comes up at least one link--and maybe two links--short. It's easy enough to add another link or two, but any idea why I am running into this problem? I don't think the chain is hanging up on anything, and we're rotating everything to account for slack, but we're coming up short no matter what we do
Yes, all the 350/750 and even the 250-305s use a 94 link camchain. I worked on a 350 last year and faced some of the camchain install challenges you mention. Certainly, getting the guide roller setup to stay down in the case, with the two damper pieces was especially challenging.
As long as you know that there is no interference along the camchain run from the crankshaft, the factors that will affect the "short chain" effect are the stack height of the cylinder, cylinder head and the gaskets between them all. Make sure that the new gaskets are the same thickness as the old ones. I have seen some variations in aftermarket parts. Leave installing the camchain tensioner to the last step, once the chain is attached.
The other thing to do to mitigate the new gasket issues is to put a socket/spacer over the ends of the cylinder studs and gently torque them down, to compress the total height of the top end components. You just need a couple on the top and bottom to help bring the height down to where the camchain can be re-strung on the sprockets.