Hello, I am new to this great forum and ready to dive into my first classic bike restoration.
I inherited my stepfathers 1965 CL77 that he purchased new. I got the bike running this past summer except that the left cylinder was not firing properly. I rebuilt the carbs and checked the timing and still got backfires and wet plugs. I did a compression test and found the left cylinder to be out of spec.
I decided to pull the engine. When I got the cylinder off, the left cylinder had a gouge from broken rings. The walls have large spots on them from rust.
When I got the bike it came with all kinds of NOS parts to include gasket set, cylinder head, exhaust pipes, shocks and much more. For some reason my stepfather only had the CL72 shop and maintenance manuals. These work great except when it comes to engine cylinder specifications.
Can somebody post the 305 cylinder diameters? I do have a NOS piston and ring set that is .25 but I am not sure if they will work since the cylinder has been gouged. Also, is the term “.50 over” mean .5 mm over the stock cylinder diameter?
Thank you.
305 Cylinder DiameterWelcome to the forum! The standard bore is 60mm, and yes .5mm. The lagest oem overbore is 1.00mm, tthough 2.00mm and 3.00mm were available back in the day, and still show up on ebay from time to time. You probably want to tahe your cylinder, and the .25 pistons to a machine shop, and get an expert opinion on whether or not it will be enough to clean up the bore. If not, piston kits come up on ebay in larger sizes, Tim McDoweel has beautiful wiseco piston kits in .5 and 1.00, and there is always the parts wanted section on this site. BTW, nice score on the bike, and especially all of those NOS parts! I'd really recommend purchsing Bill Silvers books, available through this site.
davomoto
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