Has anyone here ever heard of EVANS NPGR "waterless" coolant, this stuff is amazing, it has boiling point of 400F degrees and is good down to -10F, and when it does go below -10 it actually shrinks instead of expanding. What else ? Well, it's good for 100,000 miles! So Evans reccomends draining it into a clean pan (no matter what color it comes out) and re-using it for 100,000 miles. It goes for about $38.95 per/gal but this will do 2-3 bikes depending on size & coolant capacity and its well worth it, especially for those on 4-strokes. Keep in mind that Prestone 50/50 boils at 276F degrees, and it boils before it boils over & this creates little bubbles in the jackets which makes "hot spots", Evans doesnt have any evaporative properties. Just thought this might help.
www.evanscooling.com