alright, ive got my carb off of my 400ex sitting in front of me. what i want to know is what are the best jet sizesand needle position for a 400 with a k@n filter, stock exhaust but a possibilty of a future full system. also, whats the best for cold weather starts?.

 

Try a 152 or 155 for the main and a 40 or 42 for the pilot. Also, make sure that you are using premiun gas.

 

152 seems very big for a stock exhaust, i put a 142 in. where can i get pilot jets? The dyno jet kit i had (complete) didnt have any pilot jetds in it.

 

I am talking stock jets, the Dyna jet kits use different numbers for there jets and there is no conversion that I know of. the 400 comes with a stock 148 as the main jet. Any motorcycle parts store should have these in stock. the pilot jet is the one that has the threads on the large part of the jet, not the small part. I think it is a series 21. The Dyno kit only comes with mains and a new needle. they only care about top end power.