I just bought a pro circuit t4 pipe for my kfx400 and not for sure if it needs rejetted or not because im getting told different things. Anyone who knows if i should rejet or not would be nice.

 

slip on u dont have to. but u would gain so much from jetting its not that hard to do so i would say do it, or the pipes worthless for the most part

 

All it is, is the silencer but ill probally put a jet kit on it since it sounds like a good idea.

 

Dont rejet if your not going to pull the airbox lid off. Well if you are its only going to be about a going from a 130 to a 135 size jet. Do your selft a favor pull the lid off your air box and rejet with that slip = MORE POWER

 

rejet with a145 main and take the snorkel of the air box but leave the lide on or u will be cleaning the filter all the time and with no lide u can fill the air box up with water in a river crossing and maybe stuff a good motor but defenly rejet the header dos bugger all it is all in pipe not just a better note