E85?

[scottorious]

any ideas?

[Trafficjamz]

I don't know if it is possible. I know in cars, up to 50% larger fuel injectors are needed.

[Bear45-70]

Not a good idea. You would have to up jet and you would probably need to make a timing adjustment. Once you up jet you can't run normal gas.

[scottorious]

In my town E85 is available just about every station. Yah it would need a serious up jet for sure but much cooler running temps might be possible. Compression could be bumped up a lot as well. Plus it would be neat to say you run E85 in your scooter....to me anyway.

[Petrock's 1984 Spree]

Thatd be pretty sweet if you could get it to work.

You gotta be careful about it though. E85 is more acidic than regular gas and will chew through a metal tank a lot faster.
On those "flex-fuel" cars the have to rework a lot of the fuel system so it doesnt gunk it up or eat through it

[Bear45-70]

Alcohol has a number of traits that make it incompatible with running with gas. Alcohol burns very slow and cool, these can be good and bad. If you run straight alcohol you need to double the jet size and advance the timimg into the 60┬░ of timing advance. The cool thing is an issue that is not easy to overcome. The race guys have a * of a time getting their motor to warm up to any decent running temperatures and they don't even run a cooling system at all. On top of that alcohol has the nasty habit of pulling water out of the air and installing it in you gas tank. Never a good thing. Two strokes hate water way worse than 4 strokes. The final nasty habit of alcohol is it will only hold a specific amount of water (remember it pulls it out of the air) in suspension in the fuel tank. One micro-drop more and you now have a 3 layered gas tank. Water on the bottom, an alcohol layer next and then gasoline. Now where is you fuel pick up?

[noiseguy]

Let's not get Methanol and Ethanol confused. Methanol is super hard on everything and requires a ~50% upjet. Ethanol is a lot less corrosive and requires a upjet of 30%-40%.

Possible. All the issues Bear mentions with fuel stratification can be addressed by making sure to run the bike consistantly (E85 doesnt' store well). Benefit that you can raise compression and ignition timing as well with no knock, which means more potential power. You will lose MPG, figure a 25% loss on economy. I hope E85 is less expensive where you live that E10 by about 25% as well. Ethanol is harder on rubber seals... might eat the plastic float over a long period. Rest of your carb will stay super clean... less varnishing without the gasoline.

You need to upjet something like 40%, and that's for all circuits (idle, needle, and main.) Main is easy; for a stock Spree figure 65 -> 90 to start? No idea what you'll do for emulsion tubes... they make larger ones or you could try modifying what's there. Idle circuit you're out of luck; hopefully you can get it to idle within the screw adjustment.

That's it. Get a spare set of jets and try it out, and report back. You'll get a pat on the back and a place in the Wiki if you find something that works. If it doesn't work, well, you're out a very small amount of $ and effort. This would be a 1 hour job tops. Installing a head temp sensor and getting that too would be even more interesting.

[bc117]

just thought id add since no one mentioned it alcohol and oil don't mix (except plant based like castor/olive/canola oil etc.)
don't have any experience with e85 but i doubt 15% gas would make that much difference thats why they make HEET for gas, and ISO-HEET for diesels

[noiseguy]

OK. So add in the extra complication that you'll need to convert to a 2-stroke oil that works with Ethanol.

[hammer]

When I converted my race car from gas to methanol we had to also had change the needle and seats to get rid of the rubber tip and also to ones that would flow more fuel. Also had to increase the fuel line sizes and a belt driven fuel pump for the same reason. In fact I just bought a 780 Holley that had all the modifications done for methanol done.

Had to do pretty much the same thing when I raced karts while in high school when I made the change to methanol from gas.

There is no doubt in my mind you can covert a Spree to E85. However with what little I have worked with the stock Spree carb I doubt that it has the capacity even with modifications to make the conversion. My first step would be sourcing a larger carb.

My opinion is that 2 strokes and methanol is a match made in heaven when you get it right. But it not an easy task either. E85 might make the task easier. The 15% gas might make some of the cold starting issues go away and soften some of the other flow volume problems.

Good Luck.