Hey, i have a new slip-on exhaust coming. I didn't buy the new header, will try it with stock first and see what the performance improvement is like before doing anything else. question around rejetting tho: i've seen some references saying you have to rejet, and others saying you don't need to unless you also do the header. what's the concensus here, do i have to rejet? I know it will also give me a performance boost, but is it a requirement when putting this new exhaust on, please advise, exhaust will be here soon, don't want to put it on and do any damage to the bike!

thanks in advance for your insights,

Dave

 

I say Rejet. With the Exhaust its opening up with more air.. More Air Needs more Fuel

oh and Welcome to KF

 

Jet kits are so cheap and easy to do - there's no reason why you shouldn't. It runs a bit lean from the factory anyway - anything will help.

I say rip your airbox lid off, put the FMF on, and rejet that bitch.

 

Do yourself a favor and go to fourstrokeworks.biz and get the KLX 300 header, or find one on ebay or whatever. They can be had cheap.

The header is the first spot of restriction. You need to open both up and yes, you'll need to rejet. If you have the stock carb do a search on the forum for setting up your carb (probably a search on "carb mod" would do it, and then get the FMF jet kit as well. I can't tell you which one, I don't have the stock carb...

Call FMF or Fourstrokeworks if it makes you feel more comfortable, they're both very easy to talk too even if you're a do it yourself newbie.

 

Rejet . Loose the airbox lid. My 02c.