Catsgot9
05-06-2003, 10:39 AM
On my '02 400 I installed a HMF slip-on, along with a pro-design air sysytem. The HMF came with a 172 main jet, and they said to use this along with moving the needle I believe one notch down. I did this and the thing wouldn't hardly start, fouled two plugs. I then dropped down to a 160 main, it started a little easier, but was backfiring alot. Then I dropped down to a 155 main, it only backfires until it gets really warmed up then it quits. Also the airbox cover is still on, and has not been modified. Does it sound like I am still to rich, to lean, do I move the needle again? You guys have any ideas? :confused: