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fcr pilot jet 42 or 45

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think i might already know the answer but would like to run this past thumpertalk guys. i've recently changed my pilot jet from a 45 to a 42. when i am at the base of the mountain i ride up i have the fuel screw set at 2.75 turns but it won't stall until 4 turns out. when i am at the top of the mountain it will start to stall when the fuel screw is adjusted to 3.5 turns out. it idles well but has a small hesitation from idle to about 1/8 throttle.when i adjust the pilot circuit how many turns out should it be before the bike stalls. should i put some tape over the airbox to confirm it is a lean setting? i can't compare it to the 45 as when the 45 pilot jet was in i had a worn needle and seat, i have since replaced it

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Fuel screw is something you adjust once and do not touch or mess with again,  they say if you need to be more then 3 turns out,  you need a bigger pilot jet. 

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When you get to the top of the mountain and it stalls at 3.5 turns out compared to 4 at the the bottom of the mountain is normal. I would read the "confirming your pilot circuit in the FAQ's. Fuel screw setting will always change with altitude,temp,humidity and engine temp

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If the bike runs with the fuel screw closed, the pilot is too big.

If you have to have the fuel screw open more than 2.5 turns, the pilot is too small.

 

45 is the normal pilot. I imagine a 42 might be needed on a hot day at 8,000'

 

it is all about air density (temp/relative air pressure and humidity)

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