broken threaded rods

Discussion in 'Motorized Bicycle General Discussion' started by Crysisfreak7, Jun 23, 2014.

  1. Crysisfreak7

    Crysisfreak7 New Member

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    the threaded rods on the front of the engine for mounting have snapped and i am wondering how to get them out. they are snapped off slightly inside the engine block, could i drill a hole in them then use a screw to grab it and unscrew the rod? also where can i get more threaded rods like this.
     
  2. crassius

    crassius Well-Known Member

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    you'll probably need an extractor tool, as the threads tend to stretch a bit just before it snaps I make my own replacements out of good US steel
     
  3. Crysisfreak7

    Crysisfreak7 New Member

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    where can i find this extractor tool, and can i buy two threaded rods from you?
     
  4. Davezilla

    Davezilla New Member

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    Yup... Just ask any auto parts place that sells tools for an easy out set and they'll know just what you need, basically, you need to drill a small hole thru the stud or bolt that's left inside the block then you tap the easy out in with a small hammer then you should be able to just unscrew it out with the easy out.
     
  5. Davezilla

    Davezilla New Member

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    And definitely, buy some better studs, they use really cheap metal in these kits...
     
  6. 2door

    2door Moderator
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    Depending on how deep the studs are in the case, you might be able to grind a slot in the end of the stud and turn it out with a screwdriver. The studs just screw into the case.
    You'll need a Dremel tool or similar type grinder and a cut-off wheel to grind that slot.
    You don't need to use studs. Any hardware store should have Allen head cap screws. You'll want 6mm X 1 thread and you'll have to determine the length.

    If you've never used an extractor (Easy-Out) you'll need to be very careful and make sure you get the hole that has to be drilled exactly in the center of the old stud. This is so you don't drill into the threads in the case and damage them. An alternative is to take the engine to a machine shop and let them do it. Good luck.

    Tom
     
  7. crassius

    crassius Well-Known Member

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    for the stud, you can buy a good quality 6x1.0 bolt that is long enough, and saw the head off - I use a lot, so I buy one meter long threaded rod
     
  8. allen standley

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    I too buy the meter long 10 mm rod useful for many applications on these bikes- cheep about 6 bucks in my area. bring a nut make sure thread cut is right. And to second 2Door - dremel tool - cut a slot to fit a screwdriver into for extraction. Depth of break determines your success. I have extracted mounting studs using this method 1/16th below surface. The deeper the break the smaller the dremmel wheel needed. In other words if the break off point is deep, use a used (smaller) cutoff wheel.
     
  9. crassius

    crassius Well-Known Member

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    this set is a life-saver for getting the stud center punched (also good for getting all nine holes right in sprockets)
     

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  10. Davezilla

    Davezilla New Member

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    I really like those type center punches too... makes it near impossible to get started off center with those...

    the idea of cutting slots in the broken studs is also a really good idea and I've done that before numerous times since it's sometimes quicker than trying to drill and easy out a broken stud. In a pinch I've even used a really tiny cylindrical carbide burr in my pencil grinder to cut a slot when the broken part is below the surface, but that takes a Very steady hand and enough room to access the broken part easily.
     
  11. GearNut

    GearNut Active Member

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    Those are called transfer punches, just a little info for anyone wanting to get a set.
    If you ever need to resharpen them you will need a lathe or be very creative with a drill motor and a hand file.
     
  12. Citi-sporter

    Citi-sporter Member

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    Another thing to consider, With all this drilling and grinding going on, make sure you cover your exhaust port and intake openings with Saran Wrap or something to keep the abrasives and metal grindings from finding their way into your engine, otherwise you be back asking why your engine suddenly lost power.
     
  13. 2door

    2door Moderator
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    Very good point, Citi. Thanks for bringing it up here. Most experienced builders/mechanics take it for granted. A new builder or someone who hasn't been around engines much might not be aware of the potential damage that metal shavings can do to a cylinder wall, piston or rings. Thanks

    Tom
     

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