broken mount made engine vibrate?

Discussion in '2-Stroke Engines' started by chancecube, May 2, 2011.

  1. chancecube

    chancecube Member

    i was on a ride and my front mount broke making the motor bang on the tube. i went home and fixed the mount and went for another ride but my motor was vibrating pretty bad. my top speed went from 45 to barley 30 with a large amount of vibration. i currently have the motor apart and cant see anything wrong. would a small bend that really isnt naked to the eye cause this much vibration. if so what would you replace if you dont know whats really bent .
     

  2. motorpsycho

    motorpsycho Active Member

    so your engine mount broke, and you took the whole motor apart?
    hmmm...i think that you may have gone too far.
    I would check for cracks on the frame tube where the mount was.
     
  3. chancecube

    chancecube Member

    i tried everything to get it to work before removing it. it wouldnt stop vibrating the **** out of me. like bad, you felt you would loose control of you body fluids, bad. here is already a different motor on the bike. im taking this one apart cause i have never done so. only thing i noticed while taking it apart is that one of the piston rings was broken not like disintegrated but split in to two or 3 pieces. would this make the motor vibrate like that but still be runnable?
     
  4. motorpsycho

    motorpsycho Active Member

    if one piston ring was broken , i don't think it would cause a vibration, but it might cause low power.
     
  5. chancecube

    chancecube Member

    anyone ever heard of any bending of internal parts from a mount breaking? i dont really wanna take the bottom apart if i dont have to. i ordered a new piston and rings yesterday. guess i just replace those and clean the **** out of the motor and try it again.
     
  6. Al.Fisherman

    Al.Fisherman Active Member

    Might be a crankshaft bearing/bushing. While the piston is off move the rod up and down. Check out the wrist pin. Broken rings won't cause a vibration. Could be a case bearing, or even a clutch bearing. I'd even as a last resort check out the crankshaft itself. Never know the screw that holds the crankshaft together could of come out or loose.

    http://www.motoredbikes.com/album.php?albumid=808
     
    Last edited: May 3, 2011
  7. hammer5312

    hammer5312 Member

    makes me wonder if the actual crankcase is fracture somewhere?
    That could cause a mis-alignment, hence major vibration.....

    Plus what on the front mount actually broke?
     
  8. chancecube

    chancecube Member

    broke a bolt up front had to use a easy out to get it out. when it broke i was a ways from home. riding it back i guess did the damage.
     
  9. Al.Fisherman

    Al.Fisherman Active Member

  10. chancecube

    chancecube Member

    it had good mounts. i made a similar one like yours with a u-bolt. i guess i didnt lock it well enough and it vibrated lose but only to the point where it was hitting the bike tube. when it broke i could only go about 15 after fixing it my top speed of 45 went to 30 with crazy vibration.
    i just finished taking the motor apart. only thing i noticed was a broken ring and some play in my rod where it connects to the crank and also some in the clutch plate gear. i dont know how much play is bad play though... there are 3 bearings in the motor the one on the drive shaft is a little rough to turn.
     
  11. Stoltzee

    Stoltzee Member

    This just happened to me today. I had to find "any" bolt to make it home, and on the ride home the vibration was overly noticeable. Stopped along the way and purchased some grade #8 bolts and nuts. Now that I've read a few of these post I'm going to go out and fix it, and reset both mounts. Hope it does the trick.
     
  12. Stoltzee

    Stoltzee Member

    Four Stroke Huasheng Kit
    Well I learned something! I can't use allen head bolts on my motor mount, "OR" can I?
    I tightened the front muffler side as best as I could, and then tightened the other side while holding the shaft above the threads with channel locks until I could hold no more. Just got back from a short ride, and was amazed at how little if any vibration there was. It was utterly smooth riding. The engine does vibrate, but it's not being transferred to me.
    Synopsis; The bolts are just tight enough to hold things in place.

    All right I'll have to let you in on something. I use 3/4 inch heater hose between the frame and the mounting brackets. Doubled on the engine side.
    I also took a 1 1/2 inch muffler clamp and placed it on under the back of the engine bracket with the nuts facing the rear wheel. The square part of the clamp is pushed up against the rear stock bracket "And" on top of the curved section, locking the bracket to the frame.
    When I shut off the engine it wobbled a little just like a car engine would, (Back in the day).
    Hopefully I can get some pics to go with this latter.
     
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