Buell Blast Sprockets / Drive Belt

[samato]

I have a 2002 Buell Blast and I'm confused about the sprockets & drive belt. Can someone please explain why the rear sprocket is much wider than the drive belt? I bought the bike with a broken belt and need to replace it. At first I thought the reason it broke was because someone had used the wrong size belt. The broken belt had 139 teeth and was about an inch thinner than the rear sprocket. At first I thought "well, there's the problem; it's supposed to be 128 teeth and wider". Now I discover that there are both 139 & 128 tooth options for the belt and looking at the front sprocket, I can see that a belt any wider than the one that was on there would not fit. So what's going on? Is the front sprocket the wrong size? Is the belt the wrong size? Is everything fine and I just need to put a belt on and forget about it? Should I use 128 or 139 teeth?

Any help would be greatly appreciated.

P.S. Now I'm guessing the belt broke because someone was doing wheelies from a dead stop on this bike. Any other theories?