Broken motor mount studs

Discussion in 'Frame Mounted Engines' started by cedric, Dec 17, 2006.

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  1. cedric

    cedric Guest

    I came home from a ride and found the rear motor mount studs completely gone. The clamp was also gone too, obviously, and I am guessing it snapped in half. How did the two threaded studs come out? Is there any hope of using this motor again?


  2. gone_fishin

    gone_fishin Guest

    are you saying there are two holes where the studs used to be? or, are the two studs snapped off flush?

    sorry it's under such circumstances, but welcome, cedric :)
  3. cedric

    cedric Guest

    that's correct. there are two holes where the studs used to be. there seems to be some blackish oil leaking out of them too.

    thanks for the welcome!
  4. gone_fishin

    gone_fishin Guest

    are the threads still evident in the holes?
  5. cedric

    cedric Guest

    yes, the threads seem to be completely intact

    what is going on? *scratches head*
  6. gone_fishin

    gone_fishin Guest

    that's strange, for sure...from your replies, it seems all you should have to do is replace the studs...maybe you know someone local who could have a look at the threads?

    why it happened? dunno, not enuff pics?
  7. cedric

    cedric Guest

    sorry, i can't get pics at the moment.

    are the study basically sections of threaded rod? can i go to the home depot, get some threaded rod that fits, and cut it to size?
  8. gone_fishin

    gone_fishin Guest

    basically, yes, but use the appropriate material: i'd suggest going to an auto-parts jobber or small engine repair shop.
  9. cedric

    cedric Guest

    would the appropriate material be steel? i'm assuming home depot sells aluminum rod.

    would it be possible just to sink the right size (or *very slightly* larger bolts through the bracket right into the mounts?

    thanks alot for all your help!
  10. gone_fishin

    gone_fishin Guest

    no, don't force anything, that's not the most quality of cast alloy & it will crack...match the threads correctly, go to dax's site in the "parts" section to see what you need. i do believe peeps have used bolts...anyone else care to jump in here?
  11. tirebiter

    tirebiter Guest

    You should be able to buy metric studs or metric threaded rod at a local fastener shop. My engine has 6mm studs with 1mm pitch. The back ones are longer than the front but I didn't measure lengths cuz I didn't want to take them out.

    If you get threaded rod you should have a good way to cut it and clean up the threads on the ends. A good place to get it online is McMaster Carr if you can't find it locally. Their site is . In the search window just enter "metric stud" and you'll have choices of diameter (M6), pitch (1mm), material, grade (B7 is alloy and has good tensile strength), and length. If you know the length, ordering the right ones would be easiest but they have a 1meter length rod that would do all of them with about 30" left over. Bolts will work too but a stud is better. When you put the new ones in make sure you put some locktite on them.
  12. Edward

    Edward Guest

    If the studs are broken off flush, a dremel with a cutting disc can cut a slot in the stud end. Then use a standard screwdriver to back it out. If its below the surface take it to a machine shop. The studs are a standard item carried at most auto parts stores, but allen head cap screws M6 seem to be stronger and less likely to back out when loctite is used.
  13. cedric

    cedric Guest

    wow! thanks alot for that info tirebiter!
  14. Cookie

    Cookie Guest

    Lock tight is our friend :) after you put the motor together and everything is running go back and lock tighte every thing you can can make a motor mount out of a pc of wood and it will work but you need to have those studs

  15. cedric

    cedric Guest

    a piece of wood for a motor mount?! is that even reliable?
  16. same thing happened to me i just replaced the mount and studs works fine now but i do check on it more often
  17. davidsis

    davidsis Guest

    motor mount

    I notice those two bolts have gotten lose on me I just re-tightened them. Need to put lock tite on them.
  18. daveinblythe

    daveinblythe Guest

    just tap new holes 8mm will work fine i had the same thing happen to me the alum case will handle it fine
  19. erikvilla

    erikvilla Guest

    this also happened to my mounting studs except my studs snaped inside of the engine. luckly i was able to easy out the broken threaded rod and replace with 6mm bolts from a local auto parts store i bought nice heavy duty steel bolts and reinstalled with some locktight I havent had a problem since. Now when ever i buy a engine to install on a bike i always remove the studs they come with the kit and replace with nice steel bolts and some locktight , i have found that the studs that come with the kits bend and snap very easly. also make sure you try to tighten each side on the monting bracket close to equal.
  20. Guest

    Guest Guest

    I go to the local ACE hardware store and buy metric all-thread rods. Yes, they aren't as strong as studs but their softer composition actually allows them to stay snug a little longer upon torque down.

    I don't order online, I would rather be riding then waiting for UPS guy to show up with package.