Increasing horsepower through aftermarket exhaust

Looking for some tips on aftermarket exaust setups. Going from a stock exhaust setup to a less restrictive aftermarket setup should increase the horsepower once the carburation is reset to match the increased airflow.

I am new to the ideas of beefing up bikes, but have spent plenty time under the hood of cars doing this. For those who have modified the exhaust on their bikes, have you noticed enough of a horsepower gain to make it worthwhile?

Also, which exhaust system did you use, or would you use? The names I see the most are HMF, FMF, and Muzzy (fairly new to the ATV market).

well , i ran a IH-1 after we just rebuilt some of my motor ( cam chain , head rebuild and valve work) and the throttle response is just even more fast now . sounds badddddddd too . also for you , id run one of those mbrp pipes if they still make them , theyre nuts

I've dabbled into aftermarket pipes before...

Did a HL HP kit on my old Foreman.. the pipe that was included was a Big Gun.... and as far as I could tell all it did was make the bike 3 times more loud and noisy than before. What little gains I saw when going up hills or in thick goo was truthfully not worth the subsequent loss of hearing.

Replaced the muff on my XR (dirtbike) with a Cobra... but saw no difference cause the old pipe was rotted out and had little to no baffling in it... and the new one is darn near a straight pipe so it rattles the brains also.

The HMF pipes I've seen on most bikes at rides look good and don't seem to take up as much room as the stock mufflers... but they too are loud as hell... I think I'll just stick to stock, and keep what hearing I have left.

My recommendation is to see if there is an aftermarket CDI or performance module available for your machine (not sure if there's one out there for the polaris, but I know the one on my Brute sure did make a HUGE difference).

Ride Safe,

Chuck

i shall see soon enough with my grizzly i am going to be fixing the carb tonight with the new boots and see if i can get it running good. hopfully it will gain back the pep in its step like it had before i started screwing with it to make is BAD ASS lol blah just cost 2 years of no riding and now its not yard/driveway/trail friendly!! but soon it will be my moms problem lol.

Really didnt think about the noise factor. I dont plan on wearing ear plugs when I ride, so probably going to stick to stock.

i have an FMF pipe on mine..its definetly louder, but it didnt seem tooo much louder than stock to me. i think i need to get a jet kit for the carb now, gotta give it more gas to get going since i put the exhaust on it

It's best when ya do any exhaust modification to do it all at once (some bikes even require intake snorkeling to make the exhaust reach it's full potential i.e. Foreman 450)

Installing an aftermarket pipe usually decreases back pressure and increases noise level... but it also requires additional fuel and air intake to reach it's full potential.

High performance kits usually include the new exhaust system, the new intake system (filter, pre-filter, snorkel if necessary), hotter spark plug, and carb jets/needles.

Not making all the modifications necessary at time of exhaust modification can lead to engine damage in some cases.

Ride Safe,

Chuck

Mike if something with less noise is a concern of yours then try the MBRP exhaust for your bike.They will add more power and they arent overly loud either.A few of my friends run them on there popo's and they love them.

Thanks for the tip Scrib, I may give that brand a try when I get around to modifying the exhaust..... If I ever get around to it. Probably have to do it to the wife's bike first....

Works for me...when are we gonna get started on this?
My horses need some increasing..LOL

Oh lord, no tree will ever be safe again.

I'm gonna go out and start putting concrete pillars around my house now.

A jet kit will need to be installed with a pipe for optimum performance. But you will see hp and tq gains if done right. But it does come at the expence of your hearing.

For Polaris's the MBRP pipes, are good, and not too loud, but the HMF's are awsome, the cheapest and the best power gain, and the Loudest. the FMF's are junk to me, my buddie had one, and it fell apart after 2 years, he bought an HMF, and loves it..