At 2200 - 2800 rpm. I kept hearing this whirling noise(metalic in sound) when riding. Sounded like it was in the rear primary side area. This thing drove me nutz for months. It wasn't until I tied the front endagainst a fence and jacked the azz end up and running the bike in 5th gear in the 2200 -2800 rpm range. I heard that noise and found what was causing the problem. I had purchased the solid chrome sprocket cover, the typewithout the matching holes that line up with a stock sproket. The cosmetic part is held on by the 5 sprocket bolts. At the rpms I mentioned. Its in this range that the chrome cover resonates! I lined the inner surface and mounting hub area of cover with electrical tape and bolted it back on to the sprocket. Wah La!!! No more noise!!!

 

Good catch!

 

Genius.