I want to check the balance of rear wheel, because when I check the CVT transmission on center stand, the rear wheel have up-down movement between 2000-5000 rpm.
When take off the rear wheel, I found a very interesting sign on crank case.
The L shaped air valve cup on rear wheel rubbing the crank case.
I never heard that while riding a bike and I check tire presure maybe twice last year however the air cap also appeared rubbing sign.
That air valve faced to left, because muffler on the right side, which is very hot sometimes
Need a little adjustment, turn by hand, use some spray on until the air valve have enough clearance.
I hope nobody have same situation...