Mount gap question

Discussion in 'Frame Mounted Engines' started by mdono, May 13, 2011.

  1. mdono

    mdono New Member

    I am mounting a standard Chinese 66cc engine on an Iron Horse mountain bike with steel frame and noticed that the seat tube is slightly larger than the mount. I was wondering if this would cause stress cracks to the mount and is there anything I could use to fill the gap?


  2. Al.Fisherman

    Al.Fisherman Active Member

    Most likely it will break......... Mounting/

    What I've done is find a tube as close to your seat tube, wrap with sandpaper and sand the mount down till it flushes out. Another way I've done it is to go buy a 3/4" copper fitting/union, and split it lengthwise then start cutting to take up the space.
    Last edited: May 13, 2011
  3. mdono

    mdono New Member

    Thank you for the mount ideas Al. I'll try sanding the mount first.
  4. Al.Fisherman

    Al.Fisherman Active Member

  5. retromike3

    retromike3 Member

    don't sand the mount.

    I had the same problem with my bike. When I filed the mount to fit the bigger seat tube the mount lasted about an hour before it broke and then I had a huge amount of vibration for about thirty seconds and then the motor housing broke! I had to replace my engine. Lucky for me I bought I new one on sale when It was rumored that you could no longer inport them.

    I got the sick bike parts oversized adapter. Its worked grate so far. I know that Is set up for the down tube, but its worked really good for my seat tube and I have not had any slippage so far. I have had over eleven hours on this motor with this set up.

    Last edited: May 18, 2011