Which main Jet???

[OH2400ex]

Which main jet would provide the most power with my mods?? 02 400ex stock header pipe with slip on & Open K&N as the only 2 mods?? Several of my other friends have 400's as well and I am thinking they use a 152 main is this the best and will it allow the quad to pull harder up top??? Thanks for any help!!!

[hondaex03]

I have the same mods, look in sig., I am at 900 ft. and the Dynojet kit said to use a 170 mj.

[cals400ex]

with a pipe, filter, and open air box lid i usually start around a keihin 155-158. however, temperature and elevation play a significant role.

[400exrider707]

I had the same mods and ran a 152, then switched to a 155 and now it blows black smoke indicating rich, so I think I'm going back to the 152

[nosliw]

yea 152 is what im running and shes nice and smooth

[OH2400ex]

Yeah we do alot of drag racing and their bikes just walk off on my bike, they both have pipes, 152 Jets , and filter kits as well as different gearing. Maybe this jet will keep me closer, who knows and I am powershifting my quad as they are so rider isnt playing a huge role. Oh yeah and they are on stock tires and I run 6ply Maxxis dont think those heavy tires are helping me by any means.

[Warnerade]

more hp wont give you more top end...gearing will, and like you said they have different gears.

[OH2400ex]

It seems their bikes get me down low through the middle and uptop. We havent done any night riding and racing after my jet install but I doubt it can make up the huge difference, I was told my tires are killing me as well. My 400 smokes but so do the others so unless mine is just way down on power it must be the gearing.