Hi you all; the method I use is adjust the rear wheel as far rorward as possible. Than cut the motor chain as short as possible. Use the rear wheel axel to tighten the chain. If you are using a bicycle with a rear wheel speed changer it will keep the pedal chain tight. If you are using a single speed bike I use eithe the spring or the adjustable tightner on the pedal chain. This method stops all the trouble using the tensioner on the motor chain. The bike will run a lot better and fastet.