400ex jetting questions

[bigvforcer]

I am almost done with the rebuild of the 2003 400ex.

I have installed

416 kit
port and polish the head
took the stock snorkel off and left the hole open
white brothers r-4 exhaust
uni filter/ no airbox lid

I would like to know about where to start on the jets. I live in the louisville area at about 800 feet above sea level I believe.

thanks for the help.

start out with 2 to 3 sizes bigger than stock on the piolet and main and keep goin up untill it boggs when you hit the gas, then go down one size :D

[jak1389]

well i am starting at 160 main 40 pilot and working my way from there. many people's jetting is around this so i will check my plug after my first ride, or i will most deffiantly feel that its off.

if your too rich it will run like crap and maybe smoke a little so you will def notice, and if you dont notice that then you need to keep goin up on the mains untill you do, then go down one size, like i said earlier

[bigvforcer]

before we started it had a r-4 exhaust and a k and n. I know it had a jet kit as well. I will probably need a new plug to do an accurate plug check after running, correct?

[Speedy81304]

what you should do is start out rich and work your way down... call CT and they will help with your jetting setup.