what size main jet??

[jb400exxx]

i have a 400 ex and i just bought a pro circuit T-4 slip on, and a K&N power kit (includes air filter), and i'm going to remove the choke. i am just wondering which K&N main jet to use. i am at sea level. i also have 3 good size holes in the airbox lid, and already ground out the welds in the headers. i just bought a 42 pilot, just need to know which main i should try first. any help would be appreciatted.

[jb400exxx]

i was thinking of trying a 165 first but just checking to see what you guy have to say. i think 165 might be a little lean, but i don't know, i have never jetted anything before. so it's just a guess.

thanks

[AtvMxRider]

160 or 165 should be ok

[Quadfather]

I'm running a Yoshi slip on, K&N air filter, and three 1" holes in my air box lid, and a 165 is perfect for my setup. I believe I'm right about at sea level.