Carb help.

[farmboy1]

I have a '00 400ex. i have yet to own it a year, but would like to know a little more about my carburator before i tear into it.
My quad has HMF pipe, with an aftermarket header. I have a K&N filter on it with the lid on.
What i'm wanting to know is, before i tear into my carburator, What jets do you guys run with similarly equipped Quads?
Just would like to know what you guys run so i have an idea on If what is in my quad now is right or where to go if it needs to be changed.

Thanks for all advice!
Austin

[slightlybent47]

If it runs fine I’d leave it alone.

[moyer17901]

there is several good stickys on how to rejet it, has it ever been jetted since you put on those mods? and what octane fuel do you run?
I just dont want you to be running lean because thats what burns up everything

[farmboy1]

I have not put these mods on this quad. This is how i bought it.
i Run regular octane fuel, which is 87? i have thought about running premium fuel, but was unsure if this would help or not.

I'm not sure What main jet is in it now.
Would running premium fuel from the pump change anything?

[slightlybent47]

If it has the stock piston in it then you can run any pump gas you want. I would run the premium in it when the weather is hot, to help in reducing pre detonation. Try some 93 in it and see how it runs, your not going to be hurting anything. With the mods you have then your only going to be off maybe 1-2 numbers on the jets, witch isn’t much.

[moyer17901]

higher octane fuels dont hurt anything, but instead are actually harder to ignite, thats why higher compression requires the higher octane, if not it would be popping pistons like crazy, like bent said i would definitely run it in the summer and just try the higher octane before you rejet, jets are only like 10 bucks for a set, so its not really a big deal