Rattle/vibration noise off idle

[NS FX NYTRO]

Did a search and all I can find is the primary rattle threads at idle, which doesn't bother me that much as I know it won't hurt anything. But today was my first trip on my 2008 fx nytro (3700 miles) and I noticed while going slow through tight access trails I can hear a vibration/rattle noise. Sounds almost like a bolt that's loose with washers vibrating. I had the secondary off and torqued bolt to at least 40 ft. Lbs. all washers and that spacer in secondary we're put back on also. It also sounds like it could be the pin the holds the belt cover on at the rear. Noise goes away at normal rpm's, only audible just at and above engagement on those tight single track trails where you are creeping slowly.
Anyone have input on this?

Love the exhaust note just off idle

 

[nitris223]

It could be the belt cover pins making the sounds. The plastic on these nytros flex quite a bit so it could be twisting back and forth up and down and it just makes some sounds. I suggest a louder pipe should cure the problem.

These sleds stock are so quiet that we hear everything. When mine was stock I could hear my wife giving me the finger, I fixed that with a Hindle Exhaust, now I have to look back for the finger.

 

[NS FX NYTRO]

Hindle exhaust will be a summer add on, along with a few other things like oft relocate and whatever else I think I need after putting more miles on it this winter. can't wait for rtx se windshield to get in. Riding today with no windshield @70 mph got chilly with moto x style helmet and goggles.

 

[Dimebag]

Check the exhaust clamps under the fuel tank.

 

[Mazz]

X2 on exhaust clamps, that rattle can be very deceiving.

 

[NS FX NYTRO]

Can I see these clamps by looking under tunnel? I think I read that somewhere on here to quickly check for exhaust doughnuts. When I bought sled I placed a wet rag over muffler and it almost instantly killed the engine, so I was under the impression they were good?

 

[nitris223]

No you will have to take the seat and tank off and the shield to see the exhaust joints. They are under the fuel tank.

 

[grizztracks]

You can look down the tunnel through the holes in the bulkhead. With the engine running you can see the clamps spinning on the pipes when the donuts are bad.

 

[canoehead]

I use an inspection camera to look into the hot box. Fastest way of looking at the flex pipes and hardware.

 

[NS FX NYTRO]

I had it running and could see the clamps and what looked like Allen head bolts? By looking under tunnel with a flashlight And everything was still. Also if the doughnuts were leaking wouldn't I see he white exhaust fumes that pour out the muffler coming from around the joint where the gaskets are? I didn't see a thing puffing out under there.

 

[grizztracks]

If you are new to Yamaha 4 strokes you may be hearing the normal clutch noise that many complain about. If so, it's nothing to worry about.

 

[IA Rider]

At 3700 miles if the exhaust donuts have not been changed they are likely due. If you plug the exhaust while idling it should slow the engine down or even kill the engine. If it doesn't the donuts are leaking and the clamps are rattling.

 

[NS FX NYTRO]

Ya I already did the wet rag test over the muffler and it kills the engine quickly. I think it's just normal, but was looking to see if others have a similar noise at low rpm's just above engagement. Ie, moving slowly rough tight trail

 

[Curtis Wilson]

Ya I already did the wet rag test over the muffler and it kills the engine quickly. I think it's just normal, but was looking to see if others have a similar noise at low rpm's just above engagement. Ie, moving slowly rough tight trail

Mine does the same. When moving at lower RPM there's an on/off throttle vibration sound. It reminds me of a loose heat shield or something. Very annoying. Please post if you find it.

 

[4strokes]

loose exhaust clamp and or donut. have also seen broken exhaust or hanger from ice etc.. rattle right at on on throttle is usually exhaust related in my head