[joshlevenson]

Im probably going to get an HMF slip on for my 2004 400ex soon and would like to know if i have to rejet my quad when i put it on?[

 

[grasshopper007]

yes, with air lid off use a 170 main jet. and if you haven't already, install a 42 pilot jet. your quad will start alot easier

 

[grasshopper007]

if you want a red hmf slip on, I have one I took off my 400 just repacked it before I took it off

 

[cgrady88]

i got a hmf slip as well can i just get a header to go with it and it would help out

 

[Redracer]

Yes, most of the power is made in the head pipe

 

[grasshopper007]

a slip-on goes on a stock head pipe, an aftermarket head pipe will be bigger than stock

 

[elmerkit]

Yes you need to rejet your carb or better yet get a stage one kit.