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Motorcycle Repair/compression honda 305cb 77, 1967


Hay Bill, thanks in advance for any help on this question. I did the cam timing as per you're instructions to another person. I honed the cylinders installed new rings, set the crank at TF, the cam at the punch mark with the flat level with the case, points mark was at 12oclock, connected the chain, reset the the valve lash, torqued the head over the next few days. Here, finally, is my question, when I rotate the crank with a finger over either sparkplug hole I don't feel any compression. This was a running bike that was pushing a little oil. Carbs and exhaust were not installed, chain tensioner was set. What could l have messed up. Thanks, pete. Ps, I put a squirt of 30wt in each cyl.

Pete, You mention installing new rings, but not addressing the valves in your message. Were the valve seats checked and valves lapped in?  The cam timing is set with the RIGHT SIDE piston at TDC (T mark, not the F mark). Turning the motor over with a wrench isn't going to create much in the way of compression, but you should feel some movement of air. If you have oil in the engine, use the starter motor to spin it over with a compression gauge installed to measure your actual compression.

Hopefully, you didn't damage the rings as you brought the cylinders down over the pistons and rings. Let me know what your compression readings are. If you have access to a leakdown tester, it will let you know where the compression loss is, if that is the case. Make sure your valve lash adjustment is on the compression stroke, not the overlap stroke.

Bill Silver

Motorcycle Repair

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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