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HELP!!! with 250 jetting

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I have ttr 250. I have done the Air box mod, UNI air filter, and FMF Powercore 4 silncer. The bike is running rich i get a real strong gas smell and the spark plugs black. I leave in Idaho so the elevation is around 4500FT and always going up. I was thinking of going down on the jet sizes?

Thanks for any help.

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no stoke jetting 50 and 140. It seems like everyone goes up instead of down. so i was wondering if any one new some sizes to go down to.

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no stoke jetting 50 and 140. It seems like everyone goes up instead of down. so i was wondering if any one new some sizes to go down to.

I'm trying to remember, but I think stock in my bike was 50 and either 130 or 135 main.

but, that doesn't matter. YOu know what you've got. I'd just go to Yamaha and pick them up. They'll have the next size down in stock. Take your current jets with you so they can insure a match. I still have my stock main and pilot, let me check real quick, and if the main is smaller, i'll mail it to you and you can have it.

OK, i've got my two stock jets. 50 and a 137. You're welcome to them.

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My bad thats what i got in my bike is the 50 and 137. but thanks for the offer. I will have to go to the shop and see what they have thanks for you help.

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What year TTR 250?

The stock pilot was a 50, and most like to run 52.5, but if you always ride at higher altitude, a 50 is ok. The 45 is too lean. You won't hurt anything, but it won't start as easily and run as well.

If the bike is uncorked, with the airbox snorkel removed and exhaust unplugged, a 140 works well at sea level. At your altitude, you need 2 sizes leaner in the winter, and maybe 3 leaner in the summer. So, winter main jet 135, summer 132.5.

You're close enough now to get it to run fine, but a tweak here and there and it will run even better.

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What year TTR 250?

The stock pilot was a 50, and most like to run 52.5, but if you always ride at higher altitude, a 50 is ok. The 45 is too lean. You won't hurt anything, but it won't start as easily and run as well.

If the bike is uncorked, with the airbox snorkel removed and exhaust unplugged, a 140 works well at sea level. At your altitude, you need 2 sizes leaner in the winter, and maybe 3 leaner in the summer. So, winter main jet 135, summer 132.5.

You're close enough now to get it to run fine, but a tweak here and there and it will run even better.

Its a 02. With the stock pilot it always had to choke the bike and to start it. Even then sometimes i had a hard time starting and the bike exhaust smelt real gassy. WIth the 45 pilot jet started right up. no gas smell.

this is what i have done

02 TTR 250

Airbox snorkel out

FMF Powercore 4 muffler

UNI Air fliter

pilet jet: 45

Main jet: 135

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Its a 02. With the stock pilot it always had to choke the bike and to start it. Even then sometimes i had a hard time starting and the bike exhaust smelt real gassy. WIth the 45 pilot jet started right up. no gas smell.

this is what i have done

02 TTR 250

Airbox snorkel out

FMF Powercore 4 muffler

UNI Air fliter

pilet jet: 45

Main jet: 135

Please remind people of your altitude, that is key. That jetting at sea level would be way too lean.

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If you had to choke it to start it cold, then you are where you need to be.

An easy start without the choke indicates a rich condition.

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