I'm now well into the rebuild of my 1975 CB750F. I have recently bought another one to use for parts, the first bike came with it's engine busted (drive chain snapped) The engine on this second bike is a runner, but there seems to be a lot of rattling from the cam chain, which I have adjusted as per the manual. The engine seems to quieten down as it gets warmer and if the revs are kept above 1500rpm.
It's been over 20 years since I last had a CB750 or heard one running, I seem to remember the engines being a bit noisey at tickover and particularly when cold, but I'm unsure what is considered as normal. This engine has covered about 57,000 miles, I don't know if any previous work has been done to the engine. What is considered a reasonable life span for cam chain and tensioner, and primary drive chain? I don't mind doing a top end rebuild, but don't fancy splitting the cases to do the rest.
