I'm in the process of rebuilding my 1980 cb750f and was wondering what I should be replacing? It has 45,000 mi. On it, the Pistons and cams look good, I will be replacing the rings and all the seals and gaskets, can the valves be ground on these? I'm the origional owner but the bike has not been run in at least five years. I'm just not sure about cam chains, cam chain tensioner etc.