Tuning Help !!!!

I have a 2002 400 EX I just put (well the shop did it ) a K&N power kit (air filter, precharger, jets) and also a white brothers E - series pipe. I believe the pipe has like 13 discs on it now. I am not to sure about what jets went where and what size but. What i am trying to get to is it is not running correctly. When i start to get up in the higher RPM in like 1,2,3,4 and sometimes 5th, it seems like it is not getting enough gas it starts to choke out it seems. Does it need to have the carb retuned or more/less e-series discs on the pipe. I am a just a rider looking to go real fast and do not really know much about ATVs. As for going fast it is not happening yet cause it is not running good. I have tried running it with and without the air box lid on it but the area i ride you never know if there is going to be tons of water so i like to keep the air lid on at all time unless i am just ripping it up and down my road for awhile ?

Can you help in anyway?

[Wheelie]

Whether you are running your airbox lid or not has a great affect on the tune of your quad. If you are concerned about water, drill 4 or 6 one inch holes in the airbox lid and get some airbox vents.

Sounds like your quad is running too rich, try stepping down 2 or 3 sizes on the main jet. IMO leave the silencer alone, don't try to tune your quad by adding/removing discs.

Good Luck!!

BTW---If you're using Keihin jets, a 155main jet should hit your quads 'sweet spot'.:D

[SUPERFLY 400]

I would take it back to the shop and let them know whats up. Then again maybe they will screw it up worse. Check to see it they tighten all the clamps on your intakes at your carb. it may be sucking air. They may have also jetted it to run without the air box lid on. make sure your fuel line is not pinched or kinked. does it back fire under deceleration? Call them to see what jets they stuck in. Look at our receipt it may say. there also maybe to many disc in your pipe but find out first on what jets where insalled and the needle setting Ask if its the stock needle or if they replaced it with the dynojet needle.
BTW: I also have the K&N Power kit. I installed it myself along with my pipe. Its like ridding a different bike...what a rush!!