I´d suggest having a qualified mechanic look at it. Among anything he recommends looking at, I´d ask for a compression test and to check valve clearances. I lost one of these in pristine condition due to the disintegration of the exhaust valves on #1 and #2 cylinders. I was having problems similar to what you describe, and the mechanic I took it to first was not a motorcycle mechanic, but an automotive mechanic doing me a favor (he had the same bike for years.) I asked if a compression test would tell me anything, he figured it was something else. I rode it across country and the valves went on me. The mechanic I took it to told me the bad news, and it was due to improper valve clearances (or timing, can´t remember for sure,) maintaining the exhaust valves open partially into the combustion stroke, causing etching and eventual failure of the valves. It basically needed a new engine, (really just the cylinder head, but the engine needs to be removed to replace it, and the time to replace the cylinder head really suggests to just put a good engine in.)
You can post your question, answer or comment as a guest. Or
enter your e-mail to join the forum and get notifcations of new messages.
More 1980 Honda CB900 Custom information
Our discussion forums are intended for short messages. We also welcome more extensive motorcycle reviews.
Bikez also recommends that you check out the technical
data and the riders' rating for the 80 Honda CB900 Custom.
You can also rate it yourself. Use our efficient motorcycle
classifieds to sell or
buy
this bike. Your motorbike gets a high quality presentation. Ads are free.