hmf sport series

[400exridin121]

It seems alot of people on here have hmf pipes. I have a stock 03 400ex and am thinkin about getting one. do they increase the top speed much over stock? and are they loud?

[lpmaster]

unfortunately nothing can increase top speed but sprockets but the hmf will definately help you get to your top speed quite quickly;) without the s/a they are quite loud

[400eXr1d3rZ]

An aftermarket revbox will change your speed, but it's pretty much useless on a stock motor. HMF Sport series is a very good slip-on (and full) exhaust. Very torquey and has a good sound.

[blasterandy]

How does a rev box change top speed:ermm: I am pretty sure that the only way it will is if your stock motor can hit the limiter And unfortunatly i highly doubt that any stock motor with a slip on can do that. But if you want more speed get a taller counter sprocket. Trust me you wont like the difference since your atv wont have the power you like. If anything i would go down to get some more bottom, unless you are drag racing that is and draging a stock 400 with a pipe is like racing a yfz450 vs blaster. point being you will get creamed.:D
just my .02

[400eXr1d3rZ]

Originally posted by blasterandy
How does a rev box change top speed:ermm: I am pretty sure that the only way it will is if your stock motor can hit the limiter And unfortunatly i highly doubt that any stock motor with a slip on can do that.

If you re-read my post I said "...but it's pretty much useless on a stock motor"

On a modified motor an aftermarket revbox changes your speed by allowing your quad to rev higher. More RPM's, more speed.

[blasterandy]

I understand kindof explained it to myself :D

[250exkid]

yes HMF is nice a loude with out the stupide quiet core, and yes it would be a nice pipe if you get it full system. not exactly sure on the bottom end or top end on that tho.:macho :blah: :devil:

[400exridin121]

so there inst any slip on really that will give me more top speed?

[400eXr1d3rZ]

Originally posted by 400exridin121
so there inst any slip on really that will give me more top speed?

Nothing other than gearing changes and a revbox (for modified motors) will change speed.