2002 pro x 440

[600summit420]

ok here comes the part where i feel stupid and possibly face a "you live and you learn" type of scenario.... one of my buddies was in the market for a cheep sled of any kind to ride the trails with me. after some looking we found a local guy selling an immaculate 02 pro x 440 (with 42xx miles) for $750!!! not to get too excited we went and checked it out and found that the sled starts and idles great and the guy said that it would run great for 15 mins and then bog down...he was very upfront with the issue and was not trying to deceive us in any way...but we figured it to be an easy inexpensive fix and my pal would have a great sled to ride for a great price.....WRONG!!!...after buying the sled and trying everything imaginable...no luck...sled rips for 10-15 minutes then bogs...upon further investigation found a lot of people are having the same prob. with the same sled even someone trying to slap a lawsuit on polaris for selling this particular sled...some say 03 pistons, some say different belt...we've tried rejetting up and down, cleaning the carbs checked for clogged pipe/can, checked stator, spark is good, compression is good(around 120 on both sides)...hoping for some input before we check for bigger problems but dont know where to start....luckily snow is no good right now or there would be more frustration

 

[BB454]

440

Is this the fan 440 or the liquid? Looks like CDIs are unique to either sled so I am not sure borrowing another one to try will get you anywhere if they all have this problem. Altough it may be a heat issue and if you had a second one you could stick it on once the problem starts and see if it fixes it. If it does then you would know it's the CDI getting hot. I guess if you are brave you could try even a different year 440 CDI. Timing curves should be close but not perfect. Even still I don't think you will hurt it differance is usually in the upper RPM so if it doesn't bogg down low then you will know if it's CDI.

You might also try running it until it starts acting up and then stop and throw snow on the pipe and cool it down and see if that helps. May be heat soak on the pipe. If that is the case, an after market pipe may be the solution or maybe the pipe manufaturers can tell you how to mod the stock one to make it work. I know PSI made some pipes for the Ultra back in the day that wouldn't work and come to find out the chamber outlet was the wrong size. We sent a bunch back and they changed them and fixed the problem.

 

[GREICO1]

This has got to be the fan. If the CDI has a #3 written on it, thats good. The best solution to this issue is to install 38mm carbs. If that is not in the budget, or if you don't want to try to figure out the jetting, call Thunder Products, and get Dial-a-jets, and UFO's for your carbs. Talk to Lon so you understand how the Dial-a-Jet works, and this should make it run. Did this to about a dozen and everyone liked the results. Did 1 with the 38's and never had another issue. Oddly enough, the intake ports were the same size as the 38mm carb, but was not sent out with them since they weren't race legal. There is a lot of flow out of the pipe and no intake volume, which causes the fuel being pulled up the needle to sit in the throat of the carb creating a very rich scenario when the carb is opened again. Kind of like trying to run with the choke on. That is why it works good cold, but not warm. These sleds are a lot of fun when they run correctly, no fun when they don't. On another note, the sled that got the 38's also got the original CDI and worked flawlessly. The #3 CDI gives you the max advance throughout the timing curve, without detonation. Polaris had a #4 but apparently it sounded like there was a woodpecker in the motor at idle, and it was never released to the public. One last thing, leave the intake horns in the airbox, but shorten them a bit. Had one draw them to the bottom of the box and blew the box open starving for air!