penst8grad

Here in PA we've switched to using Ethanol instead of MTBE in gasoline. THis is a switch that is going to occur nationally very soon.

That and knowing that many autos are being manufactured to run E85 (85% ethanol 15% gas) got me wondering about how much alcohol I could run in my motorcycle.

I make biodiesel for home heating, so I always have a supply of methanol on hand. Methanol is what racers use and I'm only paying ~$2/gallon at the performance shop.

I am wondering if anyone ever saw or read anything about this.

penst8grad

Wow. This is a record for me answering my own question.

The answer

mikstr

Having previously worked for an independent fuel company whose calling card was ethanol blended gasoline, I can say that most auto and small engines can accept up to 10% ethanol without problems. However, some two-strokes in particular are a bit sensitive to the slight leaning out of the mixture (as a result of the oxygen atoms found in the alcohol molecules) resulting from ethanol use and so some manufacturers recommend going up one size on the main jet for added insurance. Given some of the many benefits that come with using ethanol blended fuels (including slightly enhanced lubricity and cleaner engine internals due to its solvent properties, to say nothing of the environmental benefits), I try to use it when possible although I generally aim for 89 octane in ethanol blends. One thing to be weary of, however, is the alcohol's tendency to absorb water. If you plan on storing your bike in a humid place and not running it for a while, it may wise to fill up (if possible) with gas that does not contain ethanol.

In terms of methanol, stay away from the stuff as it is highly corrosive to rubber (such as that found in fuel lines, diaphragms,...) so unless you plan on modifying your fuel system to make it "methanol-proof", I would suggest you don't go there. Octane boosters with methanol (and there are some as it has a higher octane rating thtan gasoline) are also a no-no for the same reasons.

cheers
Mikstr