Dynojet main jet

[NCexRider]

i'm rejetting my new 400ex. i got my dynojet kit today. i've already installed a big gun race slip-on and k&n filter and i'm planning on running no air box lid. i live @ around 800 ft elevation. the instructions say @ my elevation for stage 2 to go with the 170 main jet. this seems large. i've been hearing previously around 158-160. does dynojet measure differently? in with the DJ170 like the instructions say? thanks!!!!

[wsucougfan]

I have a K&N, HMF and no lid and I run a 165 main, and I have run anywhere from 3000 feet to sea level and it runs pure, needle on clip 3, and 3 turns out on the mix screw. I would try running the 165, if it doesnt run good, go up to the 170

[F-16Guy]

Originally posted by NCexRider
i'm rejetting my new 400ex. i got my dynojet kit today. i've already installed a big gun race slip-on and k&n filter and i'm planning on running no air box lid. i live @ around 800 ft elevation. the instructions say @ my elevation for stage 2 to go with the 170 main jet. this seems large. i've been hearing previously around 158-160. does dynojet measure differently? in with the DJ170 like the instructions say? thanks!!!!
Those instructions are very misleading. The stage 2 jetting is for heavily modified engines (piston, cam, porting, full exhaust, filter, etc.). You should be running the stage 1 jetting with your mods, even with the airbox lid off. Just follow the directions for stage 1 for your altitude and you should be fine. Also, the DJ jet are a little different from Kehin jets, so don't worry about what then number on the jet says, just follow the directions.

[ReconRider25]

i have a hmf slip on, no lid, and k&n and i went with the dynojet 170.....it was spot on perfect. slightly darker cardboard brown though. i no have no airbox at all and it seems to run fine....havent checked the plug yet though. too bad i dont have a jet any bigger in the kit incase i have to go up.:(

[F-16Guy]

I can guarantee the a DJ 170 will not be "spot on" for a 400ex with no internal mods. I'm running the 160 DJ main in my 416, so I can't see a stock engine running any bigger, no matter what your location.

[NCexRider]

thanks for all the useful feedback. the stage 2, like the stage 1, jetting instructions state that they are both for UNmodified motors. anyway, i went with the DJ 165 and it seems to be running great! thanks again!!!!!