got my 400ex back today with pro meg pipe... guys at shop didnt jet it right... it seems they jetted it for the air box lid to be removed instead of the lid being on with 8 plugged holes in it... anyway i was wondering considering that i do have to run it with the lid off to keep it from cutting out, do i have more power than i would if i were to put the right size main jet and then put the lid on..... and help, answer or advice would be appreciated

 

bring it back, tell them they diddnt do it right :-) if you can Id do it..

 

Does your quad run good with the lid off or just to the point of not cutting off?

With the lid off, you'll get more air flow and if it's jetted for that along with the increased flow through the after market exhaust, then you should have more power with that set up than putting the lid back on which would restrict the air flow and jetting down for the lid being on.

You need to consider your riding conditions though....if you ride in extremely dusty or wet conditions, you might be better served to keep the lid on and have your repair shop rejet until it's right....also with the lid on, you may need to go with an after market air filter that has more air flow than your factory filter to compliment the added flow through the new exhaust.

The more air you can pull through the engine...the more gas you can pump into it to get that power. Get squared away on how you're gonna run the air box and filter and then rejet.

 

I run my 300ex with the air box lid off through mud water everywere and haven't had any problems other than the air filter getting dirty, but i have a k&n filter with precharger and that helps keep the dirt out alot.