I keep breaking things!!!

Discussion in 'Motorized Bicycle General Discussion' started by caprirs302, Sep 28, 2010.

  1. caprirs302

    caprirs302 New Member

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    In the past few months I have severed 3 motor mount bolts (twice in the front, once in the back) and just yesterday my front motor mount bracket, which I thought would solve many problems, completely broke in two. Is there anything that is strong enough to hold the massive power of my 69cc slant head?

    Any advice would be great. I'm tired of pedaling home......bf.
     
  2. WdSjw

    WdSjw New Member

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    Maybe you could drill through the frame? drn2
     
  3. caprirs302

    caprirs302 New Member

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    I don't want to go that route for sure.

    Everything that I have had was mounted pretty solid, it just can't take the heat after awhile...
     
  4. Mind_Reader7

    Mind_Reader7 New Member

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    Take some pics of how it's mounted.
     
  5. Dave31

    Dave31 Moderator
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    If you are breaking studs and shearing off mounts I would have to say the installation of the motor is incorrect causing you these problems.
     
  6. caprirs302

    caprirs302 New Member

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    well, the last piece to go was my front motor mount from SBP. Two tabs are still securely fastened to the motor, and the rest of the mount securely fastened to the bike, but the mount spilt in two
    (actually three) pieces, which then allowed the motor to wiggle a bit, which made the chain fly off...


    very messy to put back on, 4 times, before I noticed the mount was broken and pedaled home...
     
  7. Nougat

    Nougat New Member

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    I probably would have gotten one of those mounts, too, had I known where to get them when I was building. This was last year about this time, maybe nobody even was selling them yet.

    Anyway, I had to make one myself.

    I made it out of a 1/4" hunk of welding steel from Farm and Fleet. It came as a 4" x 12" piece; I cut it down to 4" x 4", then drilled the appropriate holes for the engine side and the muffler clamp. I shimmed between the engine and the plate with that frame-drill-mount plate and some washers. It hasn't given me a bit of trouble in 400+ miles.

    Tools I used:

    Weak electric drill with a mandrel and a couple of cutting wheels
    Dull hacksaw
    Broken drill bit
     
  8. WdSjw

    WdSjw New Member

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    According to the instructions I received with my motor [Raw Motor] the mounting of the motor and proper alignment of the drive train are the most important part of the build. I must admit, I tried to mount my motor incorrectly and I did suffer the same fate as you. And my chain came off a lot of times. I was scared for a long time to open up the throttle all the way for fear that my motor would pop loose again, or the chain would come off again.

    A mechanic removed and installed a new front motor mount stud for me and I switched to regular bike chain. All is well at 35+ mph. I drilled the frame though. I asked my mechanic to check the torque and he said it was not necessary. But he checked the head bolts anyway, all were still 12lbs. Sometimes I wonder if all of these quirky checks are actually individual engine faults or eccentricities.

    I wish you the best mounting your engine and drive train. You'll get it, just be careful. .bf.
     
  9. kipharley

    kipharley New Member

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    Great advice maybe he should drill the frame the other way for for highway pegs!Kip.
     
  10. WdSjw

    WdSjw New Member

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    Drilling through the frame can be difficult though, especially if one bangs the **** out of the bar with a hammer first, like I did. My build was especially complicatied by the fact that I used the wrong sized bit and had to circle around a while to make the hole bigger. Oh well, it works fine now, but it's a permanent build. The bike would no longer be desirable without the engine.

    I am contemplating purchasing a square with a hole in the middle to reinforce the frame where the main drill punctured the frame, but for now the nut doesn't seem to be sinking into the frame too much.
     
    #10 WdSjw, Sep 28, 2010
    Last edited: Sep 28, 2010
  11. Nashville Kat

    Nashville Kat Active Member

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    Are people tightening them too much?- double bolts keep them from loosening. I put rubber foam under mine- I haven't had any problems, but it wouldn't surprise me.
     

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