Stripped threads... no problem

Discussion in 'Motorized Bicycle General Discussion' started by Tad Bit Tipsy, Mar 18, 2010.

  1. Tad Bit Tipsy

    Tad Bit Tipsy New Member

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    Had a stripped exhaust screw(allen head) and was dreading replacing the cylinder body. But I took a small hair pin and stuck it in the hole then screwed the bolt back in... instant fix!!! Almost tighter than the other screw. Thank goodness for whitey wiring!!!

    Question... If I do replace my cylinder body, do I have to break the engine in again?
     
  2. Nougat

    Nougat New Member

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    Yes, if you replace the jug, you'll go through a break-in cycle again, as the rings wear down the little bit of hone on the cylinder wall and seat themselves to the new cylinder.

    On the thread fix, what do you mean by "small hair pin"? I'm thinking it's got to be a very thin piece of wire to bend with the thread and wedge in there good. Sounds like a great fix! As long as it holds, I don't see why you shouldn't be able to run like that for a long time, but if you need to take that bolt out again, you might not be able to use that trick again.

    Oh, one more thing - was it the screw that was stripped, or the threaded hole the screw goes in to? You say stripped exhaust screw.
     
  3. Tad Bit Tipsy

    Tad Bit Tipsy New Member

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    No, its in the head threads not the screw. I replaced the studs with allen head screws. The hair pin is not a bobby bin, but one of the pins used to hold hair in buns. Very thin. It worked fine and I was able to get the screw out again to add a gasket since the old one blew out. Then I just stuck a new pin in when I replace the screw. Thanks for the advice on re-breaking in, as I will replace the body eventually.
     
  4. bairdco

    bairdco a guy who makes cool bikes

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    you could tap it with a 1/4-20 tap, and use a 1/4-20 bolt.

    the hole is the right size so you wouldn't have to drill it before tapping. that'd (probably) be more secure than a hairpin, and you wouldn't need to replace the jug.
     
  5. Tad Bit Tipsy

    Tad Bit Tipsy New Member

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    Good idea Baird, now where'd I put that tap and dye set??? Hmmm. Guess I'll see how far the pins gets me.
     
  6. Nougat

    Nougat New Member

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    For science!
     
  7. Tad Bit Tipsy

    Tad Bit Tipsy New Member

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    Mad Science that is, lol. Going out for a ride, we'll see how it holds.
     
  8. stuartracing

    stuartracing New Member

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    No need for the tap n die set if the threads already 6mm the 1/4-20 will thread right in and holds great.....
     
  9. exavid

    exavid New Member

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    Best way to repair stripped threads in aluminum is to use Helicoils. They will give you a repair that's stronger than the original and you can use the same size bolt as before. Most auto parts stores have them, not real cheap but worth it. These things are good enough to be approved for thread repairs on aircraft engines.
     
  10. Tad Bit Tipsy

    Tad Bit Tipsy New Member

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    Thanks guys. A helicoil would be great! But so far so good, bugger's all kinds of tight, he he.
     
  11. mapbike

    mapbike Active Member

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    If it ever strips out again Drill, Heli Coil it to 1/4-20 as mentioed above, use red locktite on the Heli coil and get you some 1/4-20 Grade 8 allen head bolts and you are done with that issue for ever and ever....! Just (DO NOT) PUT THE RED LOCKTITE ON THE GRADE 8 BOLTS USE BLUE ON THEM....!

    I've thought about going ahead and doing this to my intake and exhaust and motor mount threads on my extra engine so that when I get ready to set it up these things will be resolved from having issue from the Git Go.

    Good luck with the hair pin though, hope it gets you there and back a 1000 times over..!

    Happy MAPBIKING.... (Motor-Assisted-Pedal-Bike)

    .duh.:-||
     

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