I had the exact same problem 2 yrs ago. The instructions say to pull the chain taught and then over the gear from the side that does not have the tensioner. This put the chain pin that's between the links directly over a tooth instead of between the teeth of the gear. I had to turn the gear one way or the other in order to get the chain to seat. I turned it away from the side that has the tensioner and have had no problems. This process is done before the tensioner is installed. The bike had 64,000 mi. on it and I assumed the chain had stretched. I often wonder how the bike would run if I had turned the gear the other direction.
