08 yz450 question on JD needles?

I am learning that the newer yz450f carbs have had alot of upgrades to them ex: stronger AP spring and dont need all the mods since I am not having any problems with it now. My next question is needles. My JD Jet kit came with 2 needles. When I rejet the bike for my new FMF 4.1 exhaust should I use the red or blue needle? I live in ohio where altitude is around 700 to 800 above sea level or should I stick with the stock needle when rejetting the bike? Does my carb already have abetter needle in it? Thanks for any input!!! :thumbsup:

The kit also came with instructions that will specify which needle you should use, based on altitude.

Is the needles that come with the kit better to use than the factory one? I read the directions and I understand using the right one for the altitude ,But are they better to use than the factory needle? Thanks for info Grayracer....

Opinions vary. Many say they are an improvement.

Thanks again Grayracer!!!!! :thumbsup:

I live in Alabama at a low altitude as well and i used the blue needle and mine runs real good, dont know how it would run with new jets and stock needle did not try that. My bike is a 08 too. GOOD LUCK

let's hope for next yr, Yamaha finally gives us EFI bike. I'm looking forward to doing away with jetting. I rode my first EFI bike and it was pretty sweet.

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