I am helping my uncle find a motorcycle and although i would like to find him a nice SOHC they arent showing up for sale in my area (East Tennessee). So we went and looked at a 1980 cb900 custom. It seems to be in excellent cosmetic condition apart from a very bad leak from a gasket in the engine. Originally he was looking for a bike that needed few repairs, but this one is priced right (500.00) and he has another 500.00 dollars in rebuild kits including a complete engine gasket kit. I guess my main question is- how far can the engine on this bike be taken down without removing the engine from the bike? Thanks!