[herbyreed]

Originally Posted by tubes_rock

The problem with Ethanol is not the ethanol itself. It's a "feature" of the ethanol. My 1986 VT700 MOM says that it will take E10 just fine. Not any more than 10%, but up to that and it will by fine.

The problem with ethanol is that it is hygroscopic. It absorbs water. (This is the theory behind why dry-gas works.) It's also demonstrated by how the fuel tester that callmeal described works. A lesser fuel station (any fuel station for what it matters) will have a small amount of water in their tanks. With pure gas, the water sits at the bottom, below the pickup tube, so you don't get it in your vehicle. Ethanol allows the water to mix into it readily, and when you buy fuel, you're buying the water too. Not only does it kill the performance, but it also causes nasty reactions between the aluminum and brass parts in a carburetor. It literally eats them up from the inside out.

As a side-note: Never fill up at a fuel station that is getting a delivery of fuel. Not your bike, not your car, not your lawnmower! When they dump that fuel into the underground tanks, it stirs up all of the sediment, water and other crud in there, and when you fill up, you get an expensive load of sludge in your tank. I've ruined a few fuel filters getting fuel like this, and things without good filters...forget it. A lot of modern cars have integrated "lifetime" fuel filters, and if they get plugged by the gunk in this fuel, it's gonna cost you!

It's not that ethanol is bad, it's just that it makes it much easier to get water into your bike.

--Justin

My understanding of water and alcohol always was that ethanol did not absorb water as well as methanol and isopropyl alcohol do. That is why "dry gas" is always methanol or isopropyl alcohol, never ethanol. Probably ethanol does absorb some water. But absorbing the water is a good thing, not a bad thing, because the water becomes part of the fuel and is burned off in the cylinder. If there is water in your gas tank it is going to get into your carbs where it could cause problems because it can sit in the bottom of the carb bowls and be taken into the cylinder as pure water. You can't depend on it staying at the bottom of the tank and not getting into the carbs. The only way that could happen is if you never use your reserve and even then is is doubtful because there will be some mixing into the rest of the tank, particularly when you fill up - and some water could be taken into the pickup tube before it settles out again.