I had to replace the cam in my sp500, and I had taken the unit apart about two weeks ago. Every thing went together fine, except for the grounding strip on the right side of the macheine opn the top rail, it attaches there but for the life of me I can't remember where it goes to. HELPPPPPPP!

 

Top motor mount maybe? This is where my Scrambler 400 attaches but not sure on the 500, I just checked my Sportsman manual and it is the motor mount to frame ground I believe your refering to.

 

That sounds like it, if you take the right side cover off, there is a little tab attached to the underside of the top frame rail, the cable is bolted on here, but I can't remember where on the motor it attaches.....

 

It should go from the frame to the top engine mount making contact with the bracket that is bolted to the head.