Originally Posted by mud master
Hi Everyone, My Friend On A 650 Vstrom Had Similar Fuel Issues As You Are Explaining, The Bike Would Run 20 Min. And Then It Wouldn't Have Enough Power To Maintain Highway Speeds. I Traced This Problem To Alcohol Enriched Fuel. (natures Friendly Fuel, Not) When We Run Any Other Fuel Without Alcohol The Bike Has No Problems, I Feel The Alcohol Evaporates Too Fast Within The Pump And Then Causes An Air Lock, When You Turn The Engine Off, It Clears And Then It Takes About 20 Minutes For It To Build Up Again. Try Running Non Alcohol Fuels In Your Bikes And See If The Problem Goes Away. Good Luck.
try finding non alcohol fuels and get back to us.... almost impossible any more, at least around these parts it is. also, if you have alcohol vapor in the pump then you will have other issues! Alcohol (while under normal pressures) goes to vapor at about 78C, if the pump/fuel is that hot then I think that there are other problems brewing.
EDIT: additional considerations: the system pressure at the veins of the pump is going to be 15-45 psi so this will also increase the "boiling point" of the Alcohol well beyond the "normal pressures" boiling point of ~180F.