I've got an '03 prox 440 fan and was wondering what are the pros and cons of exchanging the stock OEM air box for a set of K& N filters? *How will the performance change?

The foam filters will give it lots more air, which will give it more throttle response. However, you will have to watch out because more air means leaner mixture, so you may want to check your port wash to make sure you're not too lean. They do make it louder for the driver when riding because you're drawing more air into the engine. If you like any powder riding, they work great! You don't have to worry about snowdust or loosing power because of snow plugging your airbox intake. I have a set on my XC 700, and do lots of mountain riding.

They dont require more often jetting of the machine? With K&N can I expect consist air intake, or am I re-jetting every 2 degree change? There isnt any problems with warm air intake, seeing that all the air is coming directly from underneath the hood?

Hey TaTa,

My Prox 440 F hasn't showed up yet but I'm thinking of getting the TempaFlow so I don't have to do the jetting everytime the weather changes. What do you think? Would it also solve your problem with the K&N's.

Well first off, i havent put K&N's in the sled yet, im still debating. The promising note is that Polaris changed alot of the stock pilots/main jets, so i dont think the sled will be that finicky about temp. change. Based from the spec sheet, here is the stock carb set-ups;

main jet - 330 PTO/ 320 Mag
Pilot jet - 40
Jet needle / clip position - 6HEY34 / #3
Needle jet - Q-2 (286)

At this point im still looking at which clutch weight/helix/and springs I need to run. The airbox I will decide later....

why is there diff. jets in both cylinders??? 330 in one, and 320 in the other?? I thought they were supposed to be the same?

there isnt, I thought the same thing and then i went out to check and they were both the same. I not sure what the information means yet. I just copied it right off the spec sheet I got with the sled