hard to turn sprocket

Discussion in 'General Questions' started by chevy383, Dec 29, 2014.

  1. chevy383

    chevy383 New Member

    I just got a 80cc motor after having a 49cc. I just installed the brand new motor and I went to put the chain on the motor sproket and it seemed as if it was stuck. I beat it until I got the chain on and hooked it up. I then tried starting the motor and it took a good 10-15 minutes. The bike seemed 3 times as hard to pedal. I was just wondering if there is something I could do to loosen the sproket up or if it will go away with time.

    kgyrobotron likes this.

  2. crassius

    crassius Well-Known Member

    most likely, if you look at how the chain is sitting on front sprocket, you'll find that it is trying to ride up on the teeth - some sprockets are machine stamped so that the tops of the teeth are long & flat in the direction the chain runs - this doesn't allow a chain with wide rollers to fit easily down into the valleys between teeth - if you file or grind the tips of the teeth to be pointy it will help

    if you get it to run for a while, the chain will stretch about 1/2 inch & will fit much better
  3. Ollie

    Ollie Member

    I had the same thing on both my engines. Like crassius said, once you've ridden it around for a while it will free itself up.