Motorcycle Repair: seized engine, 1976 honda cb750, cam specs

Question
Bill,
I am tearing down a 1976 Honda cb750 that has sit for 20 years.It ran fine last time it was started. It has 49k miles on it. The cam specs out fine and I just pulled the head,it will need some valve cleanup. And I almost have the cylinder off. My question is, with what I've told you should I be real concerned with the bottom end? Trany shifts ok and the bike was in a barn for th 20 years. Any and all info is appreciated,thanks, Bill

Answer
Bill, these engines do have a long life and if you kept the oil clean and the bike well maintained, the bottom end bearings should be okay... BUT...... With engines with that many miles, I would be concerned about the camchain and tensioners as well as the primary chain and tensioners.

You will have the opportunity to check the camchain tensioner rollers now that you got the cylinder head off. The tensioner rollers there are most likely like the ones for the primary chain. Once they get hardened like plastic, then they will begin to chip and eventually break up inside the motor.

Bill Silver