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Ice racing fuel milage on 300 ?

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Last year the 11' 250sx could make 1-1/2 on a 2.8 tank of fuel, this year it has the 300sx set up with #7 slide and jetting out of the book (300XC) with the main one size smaller and we can't make the half way point in a 3 hour race and then have to stop again before the end to take a couple gallons.

We raced a buddys 08' 300xc yesterday with a 3.3 tank and it was no better, can a 300 with a 170 main use 7+ gallons in three hours ?

The foats are on the low side, nothings leaking, being the race fuel runs richer would you think we'd get a little better milage setting the 300sx up to run straigh race fuel.

The idea is to make one stop in a three hour race with out resorting to a desert tank.

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Last year the 11' 250sx could make 1-1/2 on a 2.8 tank of fuel, this year it has the 300sx set up with #7 slide and jetting out of the book (300XC) with the main one size smaller and we can't make the half way point in a 3 hour race and then have to stop again before the end to take a couple gallons.

We raced a buddys 08' 300xc yesterday with a 3.3 tank and it was no better, can a 300 with a 170 main use 7+ gallons in three hours ?

The foats are on the low side, nothings leaking, being the race fuel runs richer would you think we'd get a little better milage setting the 300sx up to run straigh race fuel.

The idea is to make one stop in a three hour race with out resorting to a desert tank.

seems high, but i can't compare, I run a 145 main, and get 3 hours easy!

If it's jetted right, thats what you are going to get. when i am doing high speed desert racing in my 300 - I typically plan for 20 mpg, and usually get 25 mpg. run H&H, so 40 - 50 mile laps, fuel after each lap.

You could get better mileage by leaning it out, and it would run great, till it didn't run!

Why not go with the bigger tank if the extra stop is your issue?

Edited by carl johansson

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Last week we raced an 08' three hundred at the 3 hour in about the same temps (20's) and it was no better, so I guess it's the motor, I did get the Clockworks 3.3 tank but we most likely need 4 gallons to be able to pit once.

This same bike with the 250sx top end made it an hour and a half last year and you think you'd be on the main more with the 250.

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Last week we raced an 08' three hundred at the 3 hour in about the same temps (20's) and it was no better, so I guess it's the motor, I did get the Clockworks 3.3 tank but we most likely need 4 gallons to be able to pit once.

This same bike with the 250sx top end made it an hour and a half last year and you think you'd be on the main more with the 250.

Yes but a 300 has 20% more volume, correct? so all else being equal you have to fill 20% more space with atomized fuel every intake stroke right? So I am assuming 20% more fuel consumption is to be expected. But you are right, that assumes the same RPM rate and same mixtures, so i guess I've got nothing for you!

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