I have a 2002 Polaris Xpedition 425 that I purchased new. Has less than 1000 miles and is in great condition. I have decided it would be nice to have a bit more power, and because this one is in such nice shape I don't want or need a new one.
Does anyone know if there is a aftermarket exaust available for this model? What other upgrades could I do that are minimally invasive? (don't want to tear apart the engine).

 

yes there is an aftermarket exhaust for it, its really loud, cam upgrade isn't too bad, don't have to get too far into the motor just pull the valve cover off, get a scrambler carburetor. gain quite a bit with that

 

These guys specialize in the Fuji 500 motor, same motor as yours but a different bore or stroke.
Aaen Performance - Polaris ATV 500

They have 5 stage kits here is the last one. I,m sure there carb ,pipe and clutch kit will work on yours.

 

What brand kerbbirds? As for the cam, well like I said, I really don't want to open up the engine. It really still runs as good as new and I don't want to risk changing that.
Would just changing the exaust system make any noticable difference?

 

aaen makes a good product, hot seat performance makes stuff for it, we just put the 500 ho cam and carb in the 425 motor at first, the only difference in motors is the bore.

 

I used to have an expedition and i thought that it ran quite well on it's own. you could go up a size or two on the main jet. other than that and a full tune-up (adjusting the valves),you'll have to open up the wallet

 

If its only the bore thats different than these guys sell a 600 and 628cc big bore kit for that motor.Welcome to Four Stroke Tech.net!

Aaen stage one kit is just a pipe,thay state a 7% increase with that alone. Without motor work you can get there 42 TMX Carb and clutch kit. After that I,m sure it would beat stock 500 H.Os.

 

The bore is not the same as the 500.

About the only things you can do without going into the motor is an air filter and exhaust.

If you want an exhaust that flows well and is not loud, then find a set of 800 mufflers. But you will need access to a welder to modify the headpipe.

A Dyno-Jet kit will help some to with the exhaust and filter. But you will have to tune the carb.

If you really want to wake it up. Put the 500 jug and a high compression piston on it. This increase it to 465cc and bring the compression up to 11 to 1. But this will definitely require going into the motor.

 

i ride with one with the 500 jug, head, ho cam,and carb and it was a good upgrade