skipping in 4th and 5th

[kajunracing]

i have a 2001 400ex t-4 slip on k&n filter opened lid and running a dyno jet kit and im using a dj170 main like it calls for. and it runs awesome in 1-3 gear but skips a little in 4 and 5. does that indicate rich or lean? should i go down on my main jet?

[300exazzkikr]

The only and best way to tell is a plug check. Get to an open field of some sort where you can get the bike in 5th gear half to 3/4 throttle; hit the kill switch; roll to a stop, pull the plug and take a reading.

[shamisc]

Originally posted by 300exazzkikr
The only and best way to tell is a plug check. Get to an open field of some sort where you can get the bike in 5th gear half to 3/4 throttle; hit the kill switch; roll to a stop, pull the plug and take a reading.

What he said. A plug reading will tell all if done right!

[mopar 400]

Originally posted by kajunracing
i have a 2001 400ex t-4 slip on k&n filter opened lid and running a dyno jet kit and im using a dj170 main like it calls for. and it runs awesome in 1-3 gear but skips a little in 4 and 5. does that indicate rich or lean? should i go down on my main jet?
What do you mean by skips?

[kajunracing]

at full throtle in the upper gears it hesitates slightly but not every time! the more i read about it, it sounds like my main jet is a little rich. but im going to do the plug test first because i dont want to run lean and melt my piston!