I use the bottom of the line Amsoil which they claim is for general use BUT it is designed to be mixed at 100-1. The last time I checked Blue Duece {now blew duece} was mixing at 128-1 as I recall. Some of the guys that I've talked to as an Amsoil dealer have told me that they only run the 100-1 oil in their highly modified sleds and quads. In fact one guy {not some kid who makes waaay out claims like "my stock quad can beat quads with 10g's in 'em"} said that he ran this same oil at 200-1 then 300-1 and found no negative effects at teardown at the end of the season. Believe me, if the oil was no good it wouldn't last til the end of the day let alone the end of the season.
I run mine in the heat of summer 90's to the dead of winter -10's with no jetting changes and no negative effects. The piston crown is clean, the compression is good and there are no problems with starting or overheating.
What makes it even better is the oil is CHEAP!
An 8oz bottle will mix 5 gallons at 80-1 and 6 gallons at 100-1. that botte is around $2.50. No measuring,just pour it in the can, add gas, ride. Even at 80-1 I still get a little smoke at startup so you know everything is well coated inside for it to have to burn off excess at startup. once it's warmed up, no smoke at all. Which is nice... it doesn't look like a mosquito fogger going down the trail