Wisdom wanted

[WickedATVer]

My 400 is getting ready for the races I've rebuilt the engine. It's gona be setup like this.

426 bore, three angled stock exhaust valves and over sized intake three angled intake valves, stage 1 hotcam, White Bros R-4 exhaust, K&N air filter.

before all that with just the stage 1 hotcam r-4 exhaust and foam filter it had a 170 main jet. I want to remove the joke and make sure i have the rught main jet.
I live in Maine and would like to know what anyone thinks i should be looking for pilot and main jet size.

[underpowered]

i am running a similar set-up with:
wiseco 11:1 426 bore
stage 2 cam
HMF slip on
Choke removed

i run a 178 main jet and a 45 pilot, which i actually need to go bigger on the pilot still.

fo you with a full system and larger valves, i would try like a 185 main and a 45 or 48 pilot.

[WickedATVer]

alright, this my first time owning a four stroke but i can work on just about anything and already have the carb apart I just want to understand the just what the jets do. Now the Main Jet controls how much fuel is mixed with the air with the throttle open and the pilot controls how much fuel is mixed at idle?
Thanks for any info.:D