I was wondering if anyone new some good sprockets that would help my machine go faster or any other ways for that matter. I also wanted to know if the hmf pipe with the quit core gave any noticeable hp gain on a 400ex... thanks for the help!

 

if you replace the chain, or any sproket, replace them all at once. Up one tooth in the front, down one in the back gives you more speed. Quiet core won't really help much, only reason im piped is for the sound.. mainly Thought you bought a Lexx anyway?

 

3:1 ratio, changing 3 teeth on the rear sprocket is = to changing 1 tooth on the front sprocket.

 

thanks! i was gonna get a lex mxe but wasn't sure so i waited and is the hmf or lex mxe sound better cuz the lex is cheaper so that would be more ideal... (i have to run it under 96db)

 

ahh... thats got to stink

 

A loud quad is not necessarily a faster or more powerful quad.
A slip on HMF pipe, even with the quiet core will make a noticeable difference in power.
You then will also need to rejet. I would also open your airbox a bit by removing the lid, flip the two rear spring clips into the box and replace the lid.
This opens the back of the airbox by about a 1/4 to 1/2 an inch.
I did this to my wife's 400ex and it made a nice change in power, not to mention how much lighter the HMF is than the stock muffler.

 

thanks!... ya i don't want it loud i just want a little more throaty sound or at least better then the stock just so it sounds better... and hp... could i crack the air box lid like you said now without re-jetting it?

 

No, do not open the airbox without rejetting, you need to rejet even if you just add a slip on pipe otherwise you will run lean and that can damage your engine.

 

I notice that when i hit the gas hard let off then hit it hard again it shoots some blue smoke out of the pipe which made me think it was running rich so that's why i was thinking of opening it? or do you still think dont do it?

 

Probably means youll just need a top end rebuild in about... 20 years.