this sounds nuts but ive heard this recently. this guy my brother knows has put motor cycle oil ( yamalube) in his 350. he says it works great and is good for older motors. ive heard alot of tricks in my day but never this! lol i guess it would work but how would it be better or worse! im unsure of motorcycle oil weight or compatability with a water cooled motor. i have heard people using motorcycle oil in air compressers due to them being air cooled as well. whats youre thought on this yamalube tune up lol?