Broken studs

Discussion in 'Motorized Bicycle General Discussion' started by Evan, Jan 9, 2010.

  1. Evan

    Evan New Member

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    Well, the rear studs broke off flush with my motor. It started running weird and when I looked down the motor was kinda flopping around. So i don't know if a wire come loose causing it to miss and then shake causing the stud to break or the other way around....or ???. right now i'm having no luck drilling into the stud to try and extract it. I'm going to get a new bit and see if that works. In the meantime any thought or suggestions. I used blue locktite on the studs. also the wire connections to the coil seemed fine when i took the motor off...don't know how to tell about the plug wire itself which is stock as is everything else. The studs were made from all thread from Fastenall. Thanks
    Evan
    :-||
     
  2. Sharksfan

    Sharksfan New Member

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  3. 2door

    2door Moderator
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    Evan,
    As for removing the broken studs, center punching the stud before drilling helps keep the drill bit centered. Make sure you get the punch exactly in the middle before hitting it. If the drill you're using is reversable then there are reverse direction drill bits that will help remove the stud. Sometimes they will back out while you're drilling. At least you used the right loctite product, blue, instead of the red stuff.
    The breaking of motor mount studs is usually caused by either the engine not being seated well in the mounts, insufficient tightening of the nuts or bolts, or, mounting in any kind of resilient material such as rubber. You'll want the engine mounted as solid as possible with no movement or areas of non contact in the mounting surfaces. I have no idea what grade of all-thread you used but a better way is to get rid of the studs and go with either a grade 5 or 8 Allen head cap screw. There is no requirement to use studs and nuts. A bolt is a better choice and you only have one set of threads to be concerned with. I say use Allen head bolts because of the limited clearance provided in some places where a hex head will not clear.
    Tom
     
  4. Evan

    Evan New Member

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    I had rubber in there. The half moon mounts don't fit my seat tube post prfect so not sure what to do there. they were grade 5 studs. I'll go the allen cap bolt method once i get these out. Thanks!
    Evan
     
  5. Evan

    Evan New Member

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    Should i heat before trying to remove?
     
  6. 2door

    2door Moderator
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    Evan,
    With the blue label Loctite usually heat is not necessary. That's the beauty of it. It holds but does not require heat to break the bond. The threads will be tight all the way out but once you get them started they should come. Good luck; keep us posted.
    Tom
     
  7. Evan

    Evan New Member

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    tried a cobalt drill bit and am not getting anywhere on these studs. Any ideas on what bit to use. It barely is even making a dent.
     
  8. stv1jzgte

    stv1jzgte New Member

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    Evan do you have a welder! or access to 1 if so place a nut over the stud and weld through the nut should screw right out.
     
  9. Gareth

    Gareth New Member

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    This. Nut is optional...welder is not. It is by far the easiest method for removing these.
     
  10. Evan

    Evan New Member

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    Im a little slow , but i don't know what that last post meant. and no, i dont have a welder
     
  11. K.i.p

    K.i.p New Member

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    Cobalt drills are very tough but can be on the brittle side. That drill should have no problem cutting the stud material. Keep the RPMs on the low side and keep the preasure up to actually sheer the material and not burnish. Given that you drill is cobalt check the tip and inspect for a chipped or damaged drill point. If you have damaged the cutting edges the battle is lost. As a side note any metal cutting drill bit should make mince meat out of these studs with proper speeds and feeds. Using a left handed drill is of course the best bet as mentioned because it will help back the stud out as it drills.
     
  12. stv1jzgte

    stv1jzgte New Member

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    Id suggest you take it to someone who does and get them to do it, you slip off the stud while drilling your gunna make swiss cheese of the alloy.

    speaking from experience i made swiss cheese once then a mate said why didnt ya just weld a nut to it ......doh!
     
  13. michaelgrav

    michaelgrav New Member

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    Your bike is geared... invest in a jackshaft assembly this will eliminate the stupid chinese rear mount totally and also you will have gears when running your engine!
    .shft.
     
  14. Gareth

    Gareth New Member

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    Here is a page that explains with pictures the welder method of broken stud removal. I have a snap-on and an irwin stud and screw extractor sets. I use the mig. It works best by far. It isn't even close.



    BugShop FAQ: Tool Techniques
     
  15. K.i.p

    K.i.p New Member

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    .....didnt mean to imply drilling was the best method, just offering advice on his chosen method. I think welding something to grab onto is a pretty slick idea.

    I would not attempt to drill one out without a center-drill first with the block fixtured on a drill press or mill.
     
    #15 K.i.p, Jan 10, 2010
    Last edited: Jan 10, 2010
  16. stv1jzgte

    stv1jzgte New Member

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    That guy's awesome how detailed can ya get, not a fan of ez outs is he.
     
  17. Evan

    Evan New Member

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    Awesome info guys! I especially like the one that gives me yet another reason to get that shift kit. Thanks Y'all
    E
     

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