Gasahol Good Or Bad?

14 replies to this topic
  • Captaincautious7

Posted May 31, 2007 - 06:16 PM


I ran into a riding buddy yesterday that told me his crf450 was in the shop in pieces being rebuilt because of running gasahol. This was the opinion of the mechanic who said that carburetor, cam chain tensioner, and valves were gummed and cylinder and piston was shot. He said that there was gum in filter box from the blowback hose too. Cylinder was supposedly in good shape in recent past. I believe he said the blend was 80/20. Anyone had this problem or was his problems probably related to other things. He also runs some type of scented additive which they run in race cars, I think. Don't know to much about that other than it makes me ill to ride behind him.

  • grayracer513

Posted May 31, 2007 - 07:29 PM


Gasohol will not cause the gumming you mentioned, but it is a poor fuel, simply because ethanol is a poor fuel. Ethanol is tough on some plastics and aluminum alloys, and it has a low energy content, which you have to jet up to adjust for.

Ethanol is also hygroscopic (it absorbs water), which makes it handy for getting water out of your fuel system, but it also means that it may pull enough water out of the air to make it unusable as a fuel, too.

The gum is likely from either his additive or all the oil that blew in out of the breather, or past his flaky rings.

  • Captaincautious7

Posted June 01, 2007 - 01:49 AM


The additive I mentioned has no purpose except for smell, nothing more. I still can't recall its name but it "supposedly " will not harm a motor because it is used in race cars. So it must be the oil which makes sense. He also said that he was using the highest octane ethanol.

  • grayracer513

Posted June 01, 2007 - 07:41 AM


If the additive is any kind of castor based lube oil, and he's using it in excess (anything over an ounce per gallon), that could very well be the source of it. But since there is the same gumming in the air box from blow by, it's probably whatever he's using in the crankcase.

  • Joe_Jet

Posted June 01, 2007 - 08:50 AM


I have run E85 in both an 06 RMZ 450 and my 07 YZ450 without jetting changes. E85 is 85% Ethanol and 15% Gas. E85 has an octane rating of 105 but has less energy per gallon which means less MPG and may require jetting changes. It is available at a few stations now. The RMZ ran great on it without jetting changes and it smells nice. The YZ ran fine, but it did worsen the low end bog. The YZ would definitely need jetting changes to run properly throughout. I have also run E85 in my lawnmower with no noticeable changes and in my 04 F150 Pickup, also with no noticeable changes other than it ran great. I wouldn't run more than 1 tank full though as there may be issues with fuel system material incompatibility issues.

  • Yamahafan

Posted June 01, 2007 - 10:28 AM


I believe he said the blend was 80/20.

Most gasahol is 90% gas and 10% ethanol


  • crf-f crf-r trx cbr

Posted June 01, 2007 - 07:37 PM


i hate sunoco now......i have been so dedicated to their ultra 94 and now they add 10% ethanol......i am saddened......bp is what i run now

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • nap__kxf

Posted June 01, 2007 - 08:06 PM


the additive must have reacted with the ethanol in the gasahol.

  • Captaincautious7

Posted June 02, 2007 - 03:32 AM


Thats probably the case. I thought if there was anything to the fuel causing the gumming effect that someone here would also have heard or experienced the same problem. I need to find out what the scent additive is called but as I said earlier, it it something commonly used in race car engines, dragsters, something like that.

  • flintlock28

Posted June 02, 2007 - 03:49 PM


i hate sunoco now......i have been so dedicated to their ultra 94 and now they add 10% ethanol......i am saddened......bp is what i run now

Around here, BP uses 10% Ethanol in their 93 octane fuel.

  • Joe_Jet

Posted June 09, 2007 - 07:27 AM


Most gasoline has 10% ethanol. That is not E85 or gasohol. E85 is 85% Ethanol and 15% gasoline. E85 is 105 Octane and burns cleaner. I don't see how that could muck up a motor unless it dissolved one of his fuel system components. These bikes are made to run on 91 pump octane. Why put all that weird crap, additives, race gas, etc. in it?

  • Captaincautious7

Posted June 09, 2007 - 12:16 PM


Can anyone name the additive that I am talking about? All I know is its purpose is for scent used in race car engines? I don't know what its called or anything else about it.

  • berudd

Posted June 09, 2007 - 12:25 PM


I don't think you can really find gas anywhere anymore that does not contain 10% alcohol. At least I always see the disclaimer on the pump when I fill up my truck.

So why in the world would you add something to that gas of a race car that does nothing more than make it smell different? Do you get a trophy for that or something?

  • grayracer513

Posted June 09, 2007 - 03:03 PM


Racing fuel contains no alcohol.

It's purpose in motor fuel (in the pumps) is twofold: It adds oxygen to the combustion event for the purpose of reducing unburned hydrocarbon emissions, and it reduces the consumption of petroleum fuels by replacing them. Methyl tertiary butyl ether (MTBE) is a better fuel additive for oxygenation, but has proven to be a significant ground water pollution problem (just like the oil companies warned the Feds it would) and is increasingly being replaced by ethanol. The trouble with ethanol from this standpoint is that it is a low energy per mass fuel, and its addition to the mix reduces the energy value of the whole fuel, requiring more to be used to do the same work.

Another huge issue with ethanol is that its use in pure form (or even E85) increases CO2 and ground level ozone emissions, and increases photochemical smog (where the air turns brown).

And finally, if we were to convert the US automobile fleet to ethanol, and the entire US production of corn were diverted to ethanol production, there would not be enough of it. Think about that.

More reading:


  • APBT

Posted June 11, 2007 - 04:07 AM


[quote name='grayracer513']Racing fuel contains no alcohol.

Not exaxctly accurate. For example, in the People's Republic of New York, MTBE use has been banned completely. As a result, VP Racing Fuel can not legally ship VP U4.2, or U2 to NY. Instead, they have re-formulated these fuels to a new spec (U4e, and U2e respectively) which contains ethanol as the oxygenate. VP claims the re-formulated fuels have similar properties and power gains as the original fuels.

Related Content


yz400f throttle bog by yz400fmaniac

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • * * * * *
  • Hot  28 replies

Is the 2016 GYTR Yamaha YZ450F too fast? by Fryboy

Dirt Bike   Special Interest Forums   Pro Racing
  • * - - - -
  • Hot  241 replies

First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

Help with 2000 yz426 by weekend woods racer

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  36 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.