FMF 4.1 jetting Vs. FMF 4.1 + Power Bomb Header

Hey, i was maintaining the household bikes when i got to my old mans 1999 WR 400 (i could be mistaken on year, its possibly a 98) and noticed that it was feeling sluggish compared to what i remember.

Since we upgraded my dads exhaust i've been worrying that he hadent got the correct jetting for the new config.

see he had bought the FMF 4.1 exhaust tip and the jetting to go along with it, but shortly after i had brought home the Power Bomb Header for fathers day.

I'm concerned that the header has considerably changed the exhaust flow from what it would have been with just the exhaust tip being added.

If i could get the jetting specs for the individual FMF 4.1 exhaust tip and the FMF 4.1 with the power bomb header i may be able to put some of my concerns to rest.. I dont want to wait and figure it out until the engines ran too lean for too long.

Thanks, Erimud

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now