I agree Downunder, these engines are very tolerant of abuse. I don't know how many times I've gone off lean with my fourstrokes and thougt I'd smoked 'em. Years later they seem to be no worse for wear. One thing that I am a believer in is castor in my fuel especially during break in. I've had no problems with botton end rust or engine damage from lean runs. I've heard that the castor will polymerize at high temperatures and create a protective varnish to prevent cylinder scuffing. I'm not a chemist, but the guys who run straight synthetics seem to suffer from higher engine wear and rusted bearings here in the humid Texas climate. My favorites are Castor/Synthetic blends from Byrons and Morgan fuels. Only down side is carbon buildup in the combustion chamber and muffler that must be delt with periodically. [img]i/expressions/face-icon-small-cool.gif[/img]