polaris indy 500 vibration problems
Amsnow
Q I have a Polaris Indy 500 that vibrates badly (track and motor) when the throttle is pushed to accelerate under a load. When not under a load, it is fine. I raised the sled and pushed the throttle, and it didn’t vibrate. When I put it back on the ground, it would vibrate for a few seconds after I hit the throttle, but then the vibration would go away. It seems to idle fine. I have no problem reaching 80 mph or so, but when the snow is deep or I just take off it vibrates. I checked the track and adjusted it, and the bogie wheels all seem fine. I changed the drive belt and from what I can tell the clutch seems okay. Could you tell me where to start looking? – spsnowmobiler
A Usually that vibration would be from a bad drive belt that has a notch worn into it from burning the belt. I’m assuming that’s not the issue as you say you replaced it. If you have a drive shaft bearing that is going out, the track will loosen up and the drivers will ratchet when you put a load on it. I would bet this is the vibration that you are feeling. It could also be a driven clutch spring that is broken or came out of the notch in the helix or clutch sheave. If it were a driven spring, your engine rpm would be low at wide open throttle as the driven clutch will up-shift too fast. Backshift would also be poor and the sled would have a hard time recovering its rpm when you chop the throttle and stab it again. The reason this will cause a vibration, when you first take off or under a load, is because the belt is pulling through the driven clutch and chattering on the sheaves. It should show belt tracks on the driven clutch sheaves if this is the problem. A broken motor mount could also cause a similar issue. – Jerry Matthews, Starting Line Products
