How do you adjust the cam chain on 1980 Honda CB650?

Answer 1

There are two schools of thought that I've seen on this:

1) Honda's own service manual recommends loosening the locknut on the adjuster bolt (don't back it all the way off, or the bolt might get pulled in or something) then slowly turn the motor over by putting a very large closed wrench on the 6-sided bolt shape under your ignition cover (right side, front cover, the big outer bolt shape, not the smaller, maybe 12 or 14 sized one) Rotate it for awhile, slowly, tightening your adjuster bolt down.

The other school of thought is to start and warm up your bike, then bring it to the lowest possible idle (around 1k rpms) and loosen that lock nut, let the spring do its thing, and tighten again.

Remember two things:

1) the cam chain may already be stretched beyond practical use.

2) the tensioner may also be worn beyond use.

Either or both of these may necessitate a top end rebuild.

For more info, check sohc4.net.