best top pipe: cpi inframe or hpd atvrp8 pipes,

 

How is the dynoport for noise compared to the HSP I have a HSP speed kit on my Explorer and just can't handle the noise. The pipe seems to work good but the noise is just too annoying for the other riders. We've experimented with addition silencers on behind it and it just kills the power. Next I'm going to wrap the pipe to get rid of some of the ringing ( hopefully). Any tips? I also have the 38m/m TMX carb on it.

 

Coupled with the FMF silencer it wasnt any louder than stock.
With a 38mm carb with the Dynoport you will want to clutch it just a little.

 

Thanx everyone so much for all the replies! I'm glad now that I know to stay away from the FMF's! I knew not to buy DG, I won't buy DG anything! [img]i/expressions/face-icon-small-wink.gif[/img]
yeah, I think I will go with the Dynoport IF I even keep this thing... the way it is stock, you have to get on the gas too much to even get it moving, and the trails around my house are very tight and technical, and rocky, so you have to creep through a lot of sections, and this machine HATES creeping along... it begs for more gas and wants to speed up!
I am probably going to try and trade this thing for a friendlier trail bike, anything with a manual gearbox, and preferably, a 4 stroke. I'd love to have a 400EX.!

 

sounds like the low end jetting is rich, yours is around the year were polaris started jetting them richer as some kind of fix for the piston failures.

being a belt drive jetting can be cleaned up so that you have no bog anywere. I used to race my race mod in the local woods. it was fairly ligh switch driving though.

 

i guess you should buy something else if you want more out of it without being too noisy,dynoport is simply the loudest pipe you want to put on a 400,cauze the rpm are stock but the bark out of it is 10 hp more listenable than before,can maybe buy a set of reed or a better carb to gain a little with stock pipe,especially if you paln to resale the thing next...my 2 cents.