Best Race Fuel ????

hi, i have the 04 250r, and i want to start running race fuel in it.... i live in alaska, so our pump gas is NOT the best by any means.... well, what do you all recommend? my bike is totally stock.... with the race fuel, do i need to re-jet? also, my buddy has a 2002 wr426f, and he has the free flow intake, with the fmf powerbomb header, and the fmf power core 4 pipe, and up'd his jets... would the same fuel work for him too if we split the cost? thanks for the advice in advance !!!!

Race gas is exspensive but if you want the best I would recomend VP U4. I personally cant afford to run that so I jsut mix 110 octance 50/20 with 91 pump gas.

If you run the U4 straight, you need to increase your main jet size to realize the full benefits. This advice was directly from some VP reps at a race.

If you run the U4 straight, you need to increase your main jet size to realize the full benefits. This advice was directly from some VP reps at a race.

Normally and to be safe you should go up one size on the main but...... Sometimes the pump gas is so bad that the bike is over jetted just to make the pump fuel burn so going to the U4 that burns completely does not change the jetting too bad.

The stuff rocks.

Up in Alaska generally your temps are a tad cooler on average that most of us so a fuel like C12 will work well.

Pricing...C12is Twice as much as pump but not the 4 times as much $$$ as the U4. U4 has gone up in price 12%+ at the WD pricing level :naughty: C12 maybe 4%. and the dang frieght has almost doubled since the fall.

I have been mixing c12 with 91 pump ( 50/50) with good results. :naughty:

I was at a race shop last week when they were setting up a bike on their Mustang dyno (just before I dynoed my Cummins turbo diesel 336/685 at the wheels!!!) and they were running U4 in a 400 street bike.

They said it made something like a 3 or 4 horsepower increase, just by changing fuel and jetting for that fuel.

A guy filled his Ford Mustang with it, and it gave something like 25hp!!!

U4 works. I'm a believer. I run it in my bike. On our bikes it should be worth 1-2 hp, and it's much cheaper than a $700 pipe. You'll definitely notice a difference.

Use what you can buy conveniently and on a consistent basis.

I hear that race gas is extremely hard on four stroke engines. Is this true?

I hear that race gas is extremely hard on four stroke engines. Is this true?

Not at all.

It is better since it is easier to jet and burns way cleaner.

I would have said Union 76 until last year. Now that they are gone, VP for sure. :naughty: Steny

The only issues are the lead content, and its effect on valve and exhaust components. There are several opionions on it. Some say the lead will cushion the seats, while others say too much lead will wear the coatings off of the valves.

I took the middle of the road .. and run 50/50. :naughty:

c-12 best all around fuel :naughty:

My brother-in-law get Sunoco leaded race gas(113 octane) for his race car and I've been using that 50/50 in my two stroke. Can I use that instead of C-12?

My brother-in-law get Sunoco leaded race gas(113 octane) for his race car and I've been using that 50/50 in my two stroke. Can I use that instead of C-12?

It is a fair gas. Not the best for a single cylinder bike but it will not hurt.

Race gas from a ground storage tank is marginal for any performance gains in a bike other than detonation deterant.

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