Outlaw 500 Engine started making loud noise.

[atomic]

My '06 Polaris Outlaw has suddenly started making a loud noise. I have used it for about 20hours (it is 8 hours since the 10hour service).

The noise sounds like something is vibrating, almost like all the plastics are loose. (I have ofc checked this ;) ) It only occurs when I'm running the quad steady on mid RPM(with low or none throttle). I have had a few ATV/MX before, but I have never heard something like this. Doesn't sound good at all. It is from the engine.

It has never done this before, so I was wondering if it might be the valves, but this should have been checked on the service, right? Also the valves would have had a ticking sound, not a vibrating?
Any Ideas too what can cause this?

[OutlawBill]

It could be valves and have the side covers pulled and check the clutch and fly wheel

[Sparky_20]

if you still have a factory warranty then id get it done at a dealer. Does the vibrating change if you give it more throttle? If your at a stop and you rev it can you hear it? Id get a stethescope or even a screwdriver and put your ear up against the motor to try to pinpoint the location

[atomic]

Originally posted by Sparky_20
if you still have a factory warranty then id get it done at a dealer. Does the vibrating change if you give it more throttle? If your at a stop and you rev it can you hear it? Id get a stethescope or even a screwdriver and put your ear up against the motor to try to pinpoint the location. Also check your drive chain slack if you can only hear it while moving

There is still warranty on it, it is a 2006 model, but i bought it new in April 2007 (got it real cheap:D ). The dealership is quite far away, so i was hoping to fix it myself. (hoping it was real simple :cool: )
The sound is there even if the ATV isn't moving, its at its worst around mid range RPM. From what i can hear, it seems to be coming from the top of the engine, suggesting the valves. But as I said in the initial post I have heard valves that need adjusting before and they didn't sound anything like this at all. The whole bike vibrates, thats how I first noticed it, also seems to be worse when the engine is cold(the first 10mins or so)

[OutlawBill]

Check cam chain tension

[ZSNOW]

what are u running for octane in ur gas?

[atomic]

Originally posted by ZSNOW
what are u running for octane in ur gas?

Running normal 95' Unleaded. Same as always, since the sound occurred on the same tank of gas i don't think this is the reason.

I will check the tension ASAP.

[ZSNOW]

the reason i ask was , my ltz400 liked some gas more then others, it did not like race gas at all and and did not happen to like 95, it vibrated like a motha with it until i put the hot cams in then all it wanted was race gas and high octane pump.

[Sparky_20]

if you do figure out what it is, just get it done at the dealer. The whole point of having the warranty is so you dont have to touch it until its out. thats just my opinion tho.