Low rpm vibration

[saythey]

When riding this wkn I noticed a vibration feeling about 6000 to 7000 rpm or around 15 to 30mph. This seems to happen only in deep heavy snow. The track is tight so it is not skipping. When I am wide open and rev 8600 in the deep stuff it is fine. Can't alway ride wot in some areas. Is there a chance the belt is slipping?

 

[saythey]

Any ideas what to try and look for?

 

[Grimm]

Check/replace the drive belt.

Check the suspension components for breakage or missing parts.

 

[saythey]

If it was the belt why would it only be in heavy snow and at lower speeds and rpm.