Cracked Headpipe

[maynard22]

Well somehow my FMF headpipe cracked and my buddy has a stock headpipe that he will give me and I was wondering if I will have to rejet when I put the stocker on. I am leaving my T4 slipon on the bike, just changing the header pipe

[bwamos]

It will run rich.. but should be safe. You may also foul a few plugs.

If it's a short term fix, you should be "ok". But if it's a long term solution, you should rejet.

[zeppelin]

i really doubt it will chande your jetting significantly enough for you to need to change it at all. but if any thing it will run rich so if you start to foul plugs (which i highly doubt will happen, especialy since the 400 practicaly has oversize headers stock) try knocking the main down one

[bwamos]

If the headpipe cracked.. odds are it was probably a little lean anyway.

[h400exrydr]

mine did the same thing...a FMF power bomb right? did it crack right where the to parts that come from the motor connect? i no for sure that mine aint runnin lean..it is way on the rich side.

[maynard22]

Yep, it was a powerbomb, and that is where it cracked.

[dirtmomma]

Good Ol' FMF :rolleyes:

[hokes]

If i was you guys i would be getting ahold of them. This could be a design issue and you might be able to get a new header from them.

Like they say, the squeaky wheel gets the grease.