Bonneville America Forums Forums Technical Forums General Tech E85 (ethanol) ????

Ok, I read in my '07 manual where I can use E85 or ethanol fuel. Since it costs about 40 cents less around here I thought I would give it a try. Well, My bike sputters and I have to limp home at a mere idle with the choke on to keep running. It acts like it it starved for fuel (which I am sure it is!) But the manual said I could run ethanol! Well, I drained the fuel out, gave it to my neighbor, and filled up with regular and it runs fine.

What gives? I have the freak, Bubs and it has been jetted.

Anyone else try Ethanol? Success? Failure? Am I just an idiot? Wait, dont answer that last one.

E85 is a lot less efficient at burning than 89 octane so I'm guessing you'd need much larger jets to use it in our bikes.

Air/Fuel Ratios
- - - -Ideal - Rich Limit - Lean Limit
Gasoline 14.7:1 - 12.5:1 - 13.2:1
Methanol 6.4:1 - 5.4:1 - 5.7:1
Ethanol 9.0:1 - 6.4:1 - 7.8:1
E85 - - - 9.8:1 - 7.0:1 - 8.5:1

Thanks for posting those numbers Ed.

I've wondered in the past why if ideal air to fuel is 14.x:1, why is 13.x :1 considered a lean limit and is widely accepted as optimum?
Is it a matter of test bench optimum at 14.x vs. load & rolling resistance at 13.x ?
Anyone have a link to an explanation? I haven't been able to find one.

I see this trend follows the other fuels as well.

For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture - given perfect (ideal) "test" fuel (gasoline consisting of solely n-heptane and iso-octane).

The 14.7 really only considers a "perfect" gasoline which of course doesn't really exist.

In reality, most fuels consist of a combination of heptane, octane, a handful of other alkanes, plus additives including detergents, and possibly oxygenators such as MTBE (Methyl tertiary-butyl ether) or ethanol/methanol. These compounds all alter the stoichiometric ratio, with most of the additives pushing the ratio downward (oxygenators bring extra oxygen to the combustion event in liquid form that is released at time of combustion).

I wouldn't know any of this if I didn't have a good friend that runs an alcohol fueled 800hp dragster. That thing has jets the size of Dixie cups...

I always thought the perfect mix was around 13, I could be wrong, almost happened once before.

yes, Not correcting you just saying what I was under the impression of.

Just kidding, Ian. Got caught up in ditchdr's girl watching thread...
With a proposed range from 12.5:1 to 13.2:1 I'd agree with you that 13 is just about perfect.

Maybe the '07 is different, but my '03 manual says E10 max. The cars that can run E85 have a control switch to change the mixture.

I called all around the east coast of Australia, and asked every Triumph dealer if I could use the E10 (10% Ethanol) that is available here. All suggested I stick to PREMIUM (your higher octane stuff) BUT,... the biggest Triumph dealer in Queensland said he had a memo sent to him from Hinkler detailing how the bikes run fine on the 18% blend used in Europe!
I tried E10, no real difference to me.
AI gone, freak, 45/145's, TBS, TOR's blah blah blah.
In the scheme of things... it will only cost me $3 more to travel 600km to brisbane on the best fuel I can get, so...

If we had a real choke that limited the airflow instead of a fuel addition circuit you'd stand a better chance. At those ratios you'd need the fuel volume of two carbs dumped into each cylinder and I don't think our enrichener circuit will produce that much volume. Maybe a 240 main jet and a 90 pilot