Just finished cleaning up an Urban Express I picked up on craigslist. I ran it around the block before I did anything and it ran ok but no brakes, broken shock, etc I didnt go far on the death trap. Anyway, I got it ready to ride and changed the belt to a BX31. Instead of grabbing a stock box from the other NU50 I just used the K&N the guy had on it. The bike blasted 10 times better than I ever hoped and much better than the stock Iowa NU50. On the fourth time around the block (it was too much fun) I heard a clunk and slowly lost power and then when I went off the gas it died completely. Walked it home. Pulled the plug and it was obviously running way too lean. Won't start at all now and it was starting on one kick.
Any ideas? I suppose I could have jacked something up with the kick start gears when I put in the new belt... but that doesn't really explain why it stopped running unless thats interfering with the belt. I haven't seized a bike before but this didn't seem like even a soft seize, but I wouldn't know.