I've been rebuilding the top end of this CB100 motor recently. The old cam chain had evidently never been adjusted and flopped around so much that it gouged the case & inside of the chain tunnel.
Anyway it took us For. Ev. Er. to get the cam sprocket onto the cam last night. There just wasn't enough slack in the (new, OEM) cam chain to allow the sprocket to slip over the shoulder of the camshaft with the adjuster all the way in (loose). Finally we removed the upper tensioner bolt and were able to force a little more slack in the tensioner so that the sprocket slipped into place. Now the chain, set to be as loose as possible, is pretty damn tight. There is no way to give it any more slack - it will only tighten. Is it common for new cam chains to fit like this?