At 140 miles I had my first failure on my two stroke rig. I was just topping out a long uphill pull when the bike just coasted to a stop with the engine still running. I shut it down and decided to pedal it back home, mostly downhill anyway. I kept the speed slow on the downhill run because the engine chain was making odd noises. To make a long story shorter I found the drive sprocket's nut loose and the woodruff key missing allowing the sprocket to spin on the shaft. Unfortunately with the open bottom of the drive area the old key was missing so I couldn't see what happened to it. Surprised me since I checked the sprocket nut about 40 miles ago and it was tight. Anyhow Ace Hardware had woodruff keys and a little grinding and filing made one fit so the bike's back together again.