Race Gas Question, Please Help

moto116
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moto116
Edited Date/Time 7/23/2013 8:56pm
About 6 years ago I had a 2003 yz250f (stock) and whenever I would run race gas in it, it ran WAY better. It almost felt like it burned cooler/slower so the power was way smoother. It felt like you couldn't beat the bike hard enough, like it wouldn't over rev or vibrate like it would on pump gas. It was like the bike had less power but way smoother power. Has anyone else experienced this? Everyone I talk to calls me crazy but I noticed a huge difference.

I forgot what type of race fuel I was running and I was wondering what type of race fuel would give me this type of performance again? I know everyone is going to say that it's a waste of money without a highly modded/high compression engine. However, I have felt the difference and it is substantial. I did have to adjust the idle up on the bike when running the race gas because it wouldn't start otherwise.

Does anyone know what I'm talking about? Any help would be greatly appreciated. Thank you!
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NITRODOG
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NITRODOG 7/21/2013 3:10pm
7/21/2013 3:10pm
Sounds like maybe detonation / pre- ignition on the pump gas. Possibly caused by being too lean on the jetting, or timing too advanced, which was rectified by the high octane gas...
The Rock
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The Rock 7/21/2013 3:20pm
7/21/2013 3:20pm
Try running half regular pump gas and half hi octane pump gas. This is actually better than running all hi test and MXA proved this on the dyno a few years ago.
Paw Paw 271
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Paw Paw 271 7/21/2013 6:54pm
7/21/2013 6:54pm
Yes, I do know what you are taking about....If you run too much octane you will see just what you were seeing in the performance of the engine. The engine does run cooler as the fuel burns slower and you will lose power as the result. I would suggest that may be you were using 110 fuel.

The Shop

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bullpen658
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bullpen658 7/21/2013 7:07pm
7/21/2013 7:07pm
NITRODOG wrote:
Sounds like maybe detonation / pre- ignition on the pump gas. Possibly caused by being too lean on the jetting, or timing too advanced, which was...
Sounds like maybe detonation / pre- ignition on the pump gas. Possibly caused by being too lean on the jetting, or timing too advanced, which was rectified by the high octane gas...
Bingo!

I have tried race gas off and on and I can definitely tell a difference (on the track AND in my wallet). If I could afford it, I'd run race gas all the time but I can't even afford to buy pump gas ever since the po-po cracked down on my bitches working motel drive. It's hard for a pimp out here.

If you are unsure what kind to run, talk to someone (knowledgeable) at the local shop or call VP directly. Either way, you should get a good direction to go (based on the bike you're racing now).
ToolMaker
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ToolMaker 7/22/2013 6:35am
7/22/2013 6:35am
From what I've read most people will benefit more from a 50/50 race/pump gas mix. Straight pump gas; pre-detonation (knock), Straight race gas; burns too slow and will continue to burn while exiting the valves into the exhaust causing a higher overall temp and also decrease in power. We run 50/50 110 race gas/premium pump gas in my sons bike.
TM
gyd58
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gyd58 7/22/2013 8:19am
7/22/2013 8:19am
VP MR12 or VP Pro6 if cost is not an issue, about $20-25/gal. MR12 is not legal for AMA Pro racing and Pro6 is legal. VP T4 or VP VPR if cost is important, about $12/gallon.

A stock 250f on MR12 and mapped correctly runs way better than it ever will with any 110 or 110/pump mix.
VP Racing Fuels 7/22/2013 10:01am
7/22/2013 10:01am
moto116 wrote:
About 6 years ago I had a 2003 yz250f (stock) and whenever I would run race gas in it, it ran WAY better. It almost felt...
About 6 years ago I had a 2003 yz250f (stock) and whenever I would run race gas in it, it ran WAY better. It almost felt like it burned cooler/slower so the power was way smoother. It felt like you couldn't beat the bike hard enough, like it wouldn't over rev or vibrate like it would on pump gas. It was like the bike had less power but way smoother power. Has anyone else experienced this? Everyone I talk to calls me crazy but I noticed a huge difference.

I forgot what type of race fuel I was running and I was wondering what type of race fuel would give me this type of performance again? I know everyone is going to say that it's a waste of money without a highly modded/high compression engine. However, I have felt the difference and it is substantial. I did have to adjust the idle up on the bike when running the race gas because it wouldn't start otherwise.

Does anyone know what I'm talking about? Any help would be greatly appreciated. Thank you!
Hey moto116,

Try pouring T4 in your bike. You'll feel a substantial power gain and throttle response in a stock bike w/o the need for significant jetting or mapping changes. Also, you don't have to worry about cutting it with pump gas as it already carries a reasonable price tag for the performance offered.

VP Racing Fuels MX / Off-Road Page

Got additional questions? Call our tech - +1.812.878.2025

-VP Racing Fuels
captmoto
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captmoto 7/22/2013 1:30pm
7/22/2013 1:30pm
Avgas 100LL if it's convenient. Very easy jetting adjustments because it isn't a huge octane jump and no clean air crap or alcohol. Before everyone starts in in on the old wives tales about avgas, I've been running it in my 05 CR250 for 2 years and my 81 YZ465 for 3 YEARS. It keeps really well in steel can and mixes really well for 2 strokes. Oh yeah, $5.80 a gallon.
adub274
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adub274 7/22/2013 9:00pm
7/22/2013 9:00pm
I tried the T4 . Loved it . I did have to change the efi coupler from stock to rich . It was a little harder to start without changing the coupler . Ran awesome . I just used it at races . The first 5 gallons went for 4 races at 2 classes per race . Definitely worth it . Just can't get t here . Have to buy in Cali . Local distributor won't order it in .
jhansen510
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jhansen510 7/22/2013 9:20pm
7/22/2013 9:20pm
moto116 wrote:
About 6 years ago I had a 2003 yz250f (stock) and whenever I would run race gas in it, it ran WAY better. It almost felt...
About 6 years ago I had a 2003 yz250f (stock) and whenever I would run race gas in it, it ran WAY better. It almost felt like it burned cooler/slower so the power was way smoother. It felt like you couldn't beat the bike hard enough, like it wouldn't over rev or vibrate like it would on pump gas. It was like the bike had less power but way smoother power. Has anyone else experienced this? Everyone I talk to calls me crazy but I noticed a huge difference.

I forgot what type of race fuel I was running and I was wondering what type of race fuel would give me this type of performance again? I know everyone is going to say that it's a waste of money without a highly modded/high compression engine. However, I have felt the difference and it is substantial. I did have to adjust the idle up on the bike when running the race gas because it wouldn't start otherwise.

Does anyone know what I'm talking about? Any help would be greatly appreciated. Thank you!
VP Racing Fuels wrote:
Hey moto116, Try pouring T4 in your bike. You'll feel a substantial power gain and throttle response in a stock bike w/o the need for significant...
Hey moto116,

Try pouring T4 in your bike. You'll feel a substantial power gain and throttle response in a stock bike w/o the need for significant jetting or mapping changes. Also, you don't have to worry about cutting it with pump gas as it already carries a reasonable price tag for the performance offered.

VP Racing Fuels MX / Off-Road Page

Got additional questions? Call our tech - +1.812.878.2025

-VP Racing Fuels
I have a 13 kx250F. Is this gas good to run with the stock efi mapping? I was running u4.4 with no mapping changes but did not enjoy draining tank and putting pump gas in as I have heard not to leave the u4.4 in the bike. I am looking for good performance and also good reliability. I would also like something I can keep in the bike for lengths of time.
gyd58
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gyd58 7/23/2013 5:30am
7/23/2013 5:30am
The T4 will run better than pump with stock mapping probably not as good as the U4.4. Your bike would run even better if remapped no matter what fuel you use. My son runs T4 for practice and have had no issues leaving it in the tank. The bike is ridden 3-5 days per week.

If your bike is going to sit for any length of time pump it back into the metal can with this:

http://www.amazon.com/Sierra-Tools-Battery-Operated-Liquid-Transfer/dp/…

One of these pumps really makes emptying the tank easy.
jhansen510
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jhansen510 7/23/2013 8:56pm
7/23/2013 8:56pm
Any idea of a good place to send it off to get mapped out?

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