I have a '03 Sportsman 400. It is a great machine but more power is always better. Can you guys clue me in on some of the best ways to squeze out the most power from these little 425cc?

 

I have an '01 SP 400 and would start with a clutch kit, pipe, and filter. The clutch kit is a must...it really wakes up the bottom end and is better for the belt to boot. As far as power goes you'll never come close to the power of the 500H.O. I've kicked myself repeatedly for thinking the power of the 400 was all I would ever want. It is all I'll ever need, but not all I'll ever want. Great machine though, very reliable/ maintenance free. As far as specific brands go for the above items I'll leave that to the other guys. I've heard it's best to buy clutch kits and pipes together as a package from one manufacturer since the clutch kits in those packages are tuned to stay in the meat of the pipe's power curve. I messed up and bought a clutch kit from EPI and a pipe from Biggun. Their nice, but I can't help but think I'm missing out on a pony or 2.

 

AAEN has all kinds of power mods for Sportsmans.

 

I appologize upfront for my stupidity but... who/what is is AAEN?

 

If you want your 425 to run great check out my signiture.Mine is set up where it will hold its own with the 500s.Aaen is one of the first to make aftermarket parts for Polaris they have been at it ever since Polaris first brought out their snowmobils.Great folks to deal with.

 

the 400 is a great machine but if it's power you want then bump up to the 500 H.O. or even the 700 twin.