550 fan Motor Problems?

[Llamarider]

I have a 2002 550 fan with low miles. My inlaws bought it new and rode it around their ranch about 100 miles until it broke down. I tore into the motor this winter and found the right piston skirts had broken. I rebuilt it, and put about 60 miles on it, and the right pisotons skirts broke again??

Does anyone have any reasons why this could be occurring?? The almost identical things happened twice to this motor? It is using oil, and does was ridden under normal conditions.

Thanks,

 

[BB454]

550

Sounds like the cylinder bore is off. You need to measure it and compare to the size of the bottom of the new piston. Check the service manual for the spec. It's a little more than a liquid cooled sled because the fans see more of a temp swing.

 

[snowmanwoody]

ACCS?

does this sled have automatic carb altitude compensators on it if it does polaris had a problem with those on the 550 motor most rideres take them off and jet to proper size

 

[XCRacer440]

Those 550 fans were piles of ****. Dump it while you can, there were many updates with them. If you ran them half throttle or lower, you'll continue to blow it up. They need to be ridden wide open to not blow. Too bad it wasnt the 488 fan. The junk 550 replaced the 488. The 488 is bullet proof. I have a 97 Indy Trail with 7800 miles on the original motor and I am full throttle on the river about 90% of the time when I do ride it.

 

[T-Bone]

You aren't the first to have problems with the 550.

This horrorshow of a thread should be mandatory reading for all polaris 550 fan owners