frame breaking at front mount

Discussion in '2-Stroke Engines' started by mich_wanderr, Feb 26, 2011.

  1. mich_wanderr

    mich_wanderr New Member

    has anyone had trouble with they're frame breaking where the motor mounts ?mines done it twice at a total of 50 dollors to have it fixed:detective:

  2. Dave C

    Dave C Member

    ...I've had broken bolts where it's rubbed a groove in the frame but nothing like that. Can you post pictures?
  3. GearNut

    GearNut Active Member

    Did you use the cursed "drill a hole through your frame and put a bolt through it" front mount adapter? They are notorious for ruining many good bike frames.
  4. bluegoatwoods

    bluegoatwoods Well-Known Member

    Frame breakage is not uncommon whether it's a drill-through or wrap-around install.

    This is a huge safety issue, too.

    Like GearNut hinted at; you want to do anything but a drill-through.

    Tilt the engine so that it's seated against the tubes as flatly as you possibly can. You don't want edges pushing against the tubes. You might need to fabricate larger mounts if your frame tubes are too big.

    I also used strips of cheap leather belts for shims. I think this helped stop vibration and "slam" from damaging the tubes.

    You should take this issue seriously and get it fixed once-and-for-all.

    Good luck.
  5. mich_wanderr

    mich_wanderr New Member

    it's a 1995 schwinn chromoly clear creek. the first time he just welded it and i pulled the motor tilt down a bit and thats were it broke this time he welded a inner sleeve in the i didn't drill but the first break was on the hole for thee drink holder.
  6. GearNut

    GearNut Active Member

    Sleeving the frame tubing will certainly strengthen it. Perhaps your frame may be made of a thinner wall tubing to save weight? I don't really know.....
    Schwinn frames typically hold up well to engines mounted in them.
    Hmmmm....... How much vibration do you get out of your engine?
    Could it be stressing the frame too much?
    Are the engine mounts square and flat to the frame or is there an air gap between the mount on the engine and frame tubing, top/ bottom or center?
  7. mich_wanderr

    mich_wanderr New Member

    i have put innertube and know have leather between motor and frame.i do get a lot of vibration but the leather seems dampen itthanks for getting back with me and i'll be in touch.this bike is a every day comutter i have a trailer to do laundry and shopping and taking the dog to the park.when i figure the pic thing i'll post some
  8. GearNut

    GearNut Active Member

    Be very watchful of your motor mount studs. Any sort of padding or cushioning between the engine mounts and frame is known to break the mounting studs.
    All padding does is transfer the stresses of vibration from the frame and mounts which typically can handle it to the mounts alone and the studs are the weak link.
  9. mich_wanderr

    mich_wanderr New Member

    the studs broke the day after i put the leather in, hey if i didn't have to work on it it just would be as fun!my local hardwear does well at haveing studs and nuts,drills and taps.hey if the frame breaks again i have a specialized 'ground controll'what do to think about alum frames?its a full suspension
  10. Irish John

    Irish John Guest

    Hi Mich, I had a front downtube crack on a Micargi cruiser and that was what taught me that Micargis just weren't good enough for motorising. To fix it it needed a thicker tube steel pipe sleeve inserted over the break and then welded around the ends. Filled and painted it was barely noticeable but if you looked closely you could see the bulge in the downtube. See attached pics.
    Another Micargi snapped both top tubes at the junction with the seat tube - that needed solid bar inserts and welded up (see pics).
    The moral of my story is never buy low quality bikes because they end up costing much more than a good Schwinn very quickly. (mind you Schwinn haven't made any good cruisers this year or last) Micargi steel tube is soft as cheese and doesn't resemble proper bike frame tubing in any way.
    I have an alloy Schwinn 7 speed cruiser that has had a 66cc two stroke and two 50cc four stroke engines all frame-mounted and has 18,000kms on the clock and is still as good as new after nearly 4 years.


    Micargi Touch 7.jpg