Odd sound on my 2015 Viper

[Neonblue2]

During riding this weekend I noticed an odd sound. It seems to happen around 29mph and ~35-40mph. Most often I can hear the sound loudly when say going to up 35 mph then descending down to 29mph. But I can hear it in sustained movement as well. The odd thing is that I can't hear it at all when the backend is lifted then accelerating to 35mph then down to 29mph so it only seems to do it under load.

The best description of the noise is it almost sounds like I'm running a 2 stroke sled. I don't feel any difference in power though. And the pitch doesn't change based on speed but how loud the sound is does. If I get on the sled the sound goes away and may not come back even at the slower speeds for a while.

Since I can't repeat it at a stop I can't isolate where the sound is coming from. Anyone know what may be going on?

 

[cannondale27]

Like this:
https://ty4stroke.com/threads/viper-clutch-noise.152047/

 

[maim]

track drone?

 

[Neonblue2]

Like this:
https://ty4stroke.com/threads/viper-clutch-noise.152047/

Hmm, similar but I really don't hear it at idle, perhaps not yet... But yes, when it revs up it sounds very similar.

 

[Neonblue2]

track drone?

That's what I was used to hearing before and I love that sound....

 

[maim]

time to check the bearings then. have you serviced the one behind the brake rotor recently?

 

[cannondale27]

I would check chain tension also. If tight it will whine at about those speeds.

 

[Neonblue2]

No, I haven't... This sled is new to me last year and only had about 400 miles last year, about 600 this year so far. Which bearings do I need to check other than the ones behind the rotor?

 

[cannondale27]

No, I haven't... This sled is new to me last year and only had about 400 miles last year, about 600 this year so far. Which bearings do I need to check other than the ones behind the rotor?

Jackshaft also. Just remove secondary and pop the seal. Have you checked chain tension?

 

[Neonblue2]

Haven't done anything yet... But I plan on pulling the chain case anyway this spring for an oil change since I don't know when it was done last?

 

[cannondale27]

Very good idea. Check chain tension now. Finger tight and 1.5 turns back out from there. If its way off I would consider removing cover now and checking the Chain Tensioner bolts. They can fall out and I bet if one is out and roller is crooked it would also make some weird noise.

 

[Neonblue2]

I'm not going back up to where my sled is now for at least 3 weeks (hopefully there's still snow). But I'll definitely check that when I'm up there. In all of the "testing" did while I was riding, I could have sworn it was coming from the right front side which would put in line with the chain case. I even asked my bro in law what it may sound like if there was a problem with it.