Funny how you take Indy Dans word as the bible. He is a very good engine builder but he is also very closed minded about certain things. He hates amsoil, so you do too! His big problem with it, is that it does little to prohibit corrosion in a stored engine. For years almost all synthetics had no corrosion resistance and half the guys in this area store their sleds under covers that hold moisture in....thats a bad thing to do! Synthetics are mostly mineral based, but take the heat much better than straight mineral oil. Three thousand miles on my 900 and never cleaned the valves, checked them but never cleaned, 50/1 amsoil interseptor. That does not make it the best, but far from the worst. If you are more concerend with how much of the oil burns compared to how much get run throught the exhasut, then "maybe" you're right, mineral oils do burn better. (I don't think so) I'm more concerened that my crank and wrist pins are getting protected and synthetics do a better job at that. You don't have to run a crank submerged in oil as long as the oil will hold a film on the bearing. Almost all the new diesel engines require a syntetic or a blend oil. This is due to the extra heat and pressures in todays engines to meet the new emissions. The oil companys were happy selling their mineral oils but found out they would break down too fast in todays extra demand engines. All of the "mineral" oils run a lot of additives to build their oils into something that will work, so basically they are semi synthetic!
