I ran into a riding buddy yesterday that told me his crf450 was in the shop in pieces being rebuilt because of running gasahol. This was the opinion of the mechanic who said that carburetor, cam chain tensioner, and valves were gummed and cylinder and piston was shot. He said that there was gum in filter box from the blowback hose too. Cylinder was supposedly in good shape in recent past. I believe he said the blend was 80/20. Anyone had this problem or was his problems probably related to other things. He also runs some type of scented additive which they run in race cars, I think. Don't know to much about that other than it makes me ill to ride behind him.