race gas.

[stainlesscycle]

so i ran out of race gas (i normally run 50/50 93/sunoco 112) last week. since this motor i've been running has a big squish (2mm or so) i was gonna try running straight 93. i've run 2 races, and 1 trail ride with it, and am not happy... the temperature and elevation has been relatively the same. i jetted for race gas mix originally.

in the past the only reason i've run race gas is stop pinging on higher compression/advanced timing. i never really thought about the possible performance increases. i really kinda felt i'd never really feel the difference.

on race gas i get snappy, and crisp jetting. with nice over rev and quick throttle response.

on 93 i get mushy midrange - and a dull exhaust tone - and it doesn't want to rev out/over rev. it's kinda just lifeless. the grunt is still there. but the mid and top are flat. it's fine when i start it, but it gets progressively worse after it gets good and hot.


is it possible all of this is the effects of race gas, or could something else be causing these problems? the only thing i've touched in the last 2 weeks aside from changing gas is cleaning the air filter.


i remember a post a while back from roostafish mentioning his weaning off of race gas - i haven't seen a post from him in a while - i'd love to hear his results, and if he found the same results. i could rejet, but it might be just easier (although not as convenient) to run race gas. cost is not an issue. when i mix race gas it ends up only costing maybe $4-$5 a tank more...

suggestions? i've always been skeptical of the hype of high octane/race gas (get more hp etc...) - but it's feeling like there is really a difference...

[GMP]

I used to do exactly what you do for years, to minimize the ethanol and effects of seasonal blend changes. Once VP went north of $8/gal., I decided to just run pump 93 (Gulf) with some Startron. Honestly, I have no problems and my bike runs great. If your jetted for a basic (non-oxegenated) race fuel like Sunoco, your going to be a little leaner on 100% pump fuel due to the ethanol.

[stainlesscycle]

did you need to rejet at all for 93? i've only jetted with the mix.... the dull mushy midrange sounds like the needle is rich to me... which doesn't make sense if reg gas with ethanol is approx 10% leaner..

with 93 it idles the same, it just gets flat in the mid, and doesn't want to get on the pipe. i can tinker with the throttle a bit and it'll get on the main and rev out. but the longer i ran it the harder this became, like i was loading it up...

haven't had a chance to pull the plug and look.

[lankydoug]

I don't trust pump fuel with ethanol in any amount, + depending on the humidity and how much moisture the ethanol has absorbed there is no way to insure against corrosion. After I moved to MO and all pump fuel has 10% ethanol I've been running 100% VP110 race fuel. If I mix 50% it only saves about $2 per gallon so I just quit worrying about it and now use pure race fuel.

My EC200, which I think could use a head mod, will run on pure pump gas but I still use VP110. My Husky on the other hand tries to ping on pump fuel.

[GMP]

The JD Blue needle is perfect with pump gas in my 250. Runs like a raped ape, just missed a holeshot today (2nd) against a mixed row with a lot of 450s. I don't hurt for power. Yeah, ethanol sucks, and race gas is nice but I have to draw the line on cost, its just too expensive and I have to drive a half hour to get it. If I had a problem I could not deal with any other way then you do what you have to do, but in my case its just not necessary. Maybe its the Startron additive that makes a difference. I also store it in a steel can and no longer than a week or so.

[ucrtwf]

I'm certainly not a GG jetting expert. Having exactly ONE ride on the bike. That being said, I've played with many different engines, and have done a considerable amount of tinkering. I've always felt that although race gas is more consistent, if I have only used it if it was NEEDED. I had a barrel of Sunoco Supreme when I ran my turbo bike, I only used it when I turned up the boost. The jetting differences were very noticeable, I would think unless you've got detanation, why not just jet for pump gas with a little juice to help with the ethanol? Just a thought.

[stainlesscycle]

i need to run race gas in 2 other bikes i have, so i usually have it on hand. i generally only use it out of necessity. my last gg needed it (1.2mm squish) - it pinged on 93... i guess i just got used to using race gas. i have one more race until jan. i'll pick up a few gallons of race gas and see if that is in fact the problem. if not, i'm back to jetting again. it's probably just a needle move, no big deal.

[GMP]

My squish is 1.1 -1.2, and compression over 190PSI with a fresh top end. This was done by Ron for pump gas, and he nailed it. A 300 should have slightly less compression. No ping as jetted even on the high map setting. 300s are a little harder to dial in jetting compared to 250s, same carb bigger signature makes them more sensitive. I think you just have to fine tune things a bit more and you will be fine.

[lankydoug]

I don't buy the saving money argument for mixing 50% race and pump. If you're mixing $3.50 per gal. pump with $8 race you're still spending $5.75 per gallon so you are saving $2.25 per gal. Now when the ethanol ruins the rubber gasket in your gas cap or screws up your aftermarket fuel tank or maybe causes some corrosion that ruins your day of riding after you towed your bikes 100 miles to ride in a really cool spot, you are out $35 to $100 or more if you're unlucky. Yes you saved $4.50 on that cheap tank of gas but you just spent enough to make up for the next 7-25 tanks that you could have been using VP110 and having no problems with. Plus race fuel does not need Sta-bil or Star-tron because it doesn't contain the cheap distillates that break down. All you have to do is keep it sealed up and out of the sun so the lead will stay suspended in it. When you run the cheap stuff you probably pour out enough old fuel to make up for 1/4 of what you save anyway. I was reluctant to buy race fuel at first but I had no choice since my Husky would ping on pump fuel unless I jetted it so rich that it fouled plugs. Now I've realized a the little I was saving on fuel was costing me more than it was worth. I'm lucky to have a place to buy race fuel 3 miles from my house but if it was far away I would just buy it in bulk 30 or 50 gallon barrels.

[stainlesscycle]

i buy it for under $8 a gallon, 10 gallons at a time. which lasts longer than you would expect since you're only using about a gallon a tank... i have to travel 75 minutes round trip. i know i've never had a bike ping once i switched to race gas. i store it flip top jerry cans i bought at a flea market for $5.00 each - the guy had 6 of them, i shoulda bought them all.... overall it's totally worth it. if i was buying vp or klotz in the cans at $12 a gallon, i would probably rethink it...