is my jet too big?

[Bush0102]

i have an hmf slip on and a k&n airfilter, and i dont run an airbox lid. The jet i was supplied with was a 170 mainjet...is that too big? am i going to have problems at higher elevation?

[400ex men]

well maybe a lil to big but i had a 180 in mine with a x-6 so you ok:)

[devildriver422]

what about mine, up one size in main jet for a yoshi rs-3 slip-on, 400ex

[Steve-o 400EX]

where are you located? I only run a 158 in my 416.

[pead_24]

i have a HMF slip on and with the airbox lid off mine ran fine with a 170 main jet in now i put li dback on and installed a 158 and that also runs good

[cals400ex]

at higher elevations, you will need a smaller jet. however, i say your way too big now too. i am located at 625 ft above sea level and in the summer with the air box lid off i would try a keihin 155 mainjet. in the winter i would go to a keihin 158.