Put a k&n on my brothers P400. Didnt run good so we got the dynojet kit. tried 138 jet that was recomended. put needle in 4th notch, and fifth notch. turned screw out 3.5 turns. starts great, idles smooth, but hesitates off idle and full throttle is the same as half. (no difference). tried 142 jet ( no different). Tried with and without lid. (worse without lid) Plug looks the same as it did before we started. Im pretty much at sea level. No backfires through carb or exhaust. Im stumped[img]i/expressions/face-icon-small-confused.gif[/img]

 

somebody?? anybody??? Trying to get his running good before all my toys get here.

 

Did it run good before the K&N filter? Is the K&N properly oiled? Does it run worse with the jet kit in?

 

it still sounds lean..im no pro for sure but jetting isnt a precise art..keep going up till you find your rich..novakaw asked a good one..improper oil on the k&n will give alot more air flow..is it oild properly?

 

It ran very well before we started, (just trying to get a bit more out of it) Oiled is a good question Didnt think about that, it is straight out of the box (new) not sure if they are pre oiled or not. I will check that. I did try with and without prefilter to. It didnt run good with just the filter, but it didnt run much better after the jet kit. Thanks for replying guys, It is appreciated.

Can needle being shimed wrong cause the problem at mid and full throttle or is it just for down low?

 

filters dont work at all w/o the oil..great way to kill a motor..