Engine Trouble Engine stud hole stripped

Discussion in '2-Stroke Engines' started by dotcom, Feb 24, 2016.

  1. dotcom

    dotcom Member

    What's a cost effective way to fix? I can only use 3 studs to torque down the head but it sounds like im riding with a blown gasket. What options would I have since one of the holes is stripped? I even tried with a new bolt but it seems in stripped internally in the case. Inexpensive solutions preferred please
     

  2. bakaneko

    bakaneko Active Member

    You can wrap a hose clamp around the missing bolt area and engine. Just gotta get the right size clamp and angle of attack correct. Then tighten the clamp with a flat head screw driver + wrench. The hose clamps are about 1-2 dollars for this size depending on where you live at Home Depot, Menards, etc. Not pretty but she will hold.
     
  3. butre

    butre Well-Known Member

    this is a terrible idea. helicoils is going to be the cheapest way to fix other than drilling it all out for larger studs and the easiest way to fix other than replacing the whole engine.

    http://www.amazon.com/Helicoil-5546-8-Metric-Coarse-Thread/dp/B0002SREP4

    you get an insert tool, a tap, and enough helicoils to do a dozen holes with this kit
     
  4. bakaneko

    bakaneko Active Member

    he said cheap...
     
  5. crassius

    crassius Well-Known Member

    if you have a tap&die set, you can tap it to put in a brass bolt, saw & file bolt flush with case, and drill and tap that bolt to take the stud - works as well as helicoil & brass has about same heat expansion as aluminum
     
    dotcom likes this.
  6. 45u

    45u Active Member

    Go to a machine shop and see if the have a thread repair kit like Heilcoil kit. Before I ever start a motor bike engine I will pull the studs and make sure the threads are good and deep enough.
     
  7. butre

    butre Well-Known Member

    he also wants something that actually works. I could tell him to just slather some jb weld on it and hope for the best and it'll probably still have better results than a hose clamp
     
  8. dotcom

    dotcom Member

    I think I will go with the hose clamp, NOT! HAHA
    Seriously, I think I will go with the helicoil but I have a couple questions.
    The helicoil kit at this ebay link is only $15.99 with free shipping compared to the Amazon listing that butre provided and they seems like the same thing but if I am wrong please do let me know.I have never purchased one and want it easier on the pocket but dont want to get the wrong one.
    http://www.ebay.com/itm/131630780653?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
     
  9. bakaneko

    bakaneko Active Member

    I used the hose clamp when I was too lazy to replace a sheared engine bolt because the bolt was really stuck. It does work but it isn't great. You never mentioned what is your price range only an inexpensive solution, which I take as dirt cheap. Seriously, I wouldn't mention something unless it works and will get you around until you figure out something more permanent. Its regrettable that someone trying to help gets so much sarcastic flame.
     
  10. butre

    butre Well-Known Member

    the one I listed comes with 4 times as many helicoils
     
  11. BWB

    BWB New Member

    That is a good price on the heli coil kit. And since you stripped one the others are most likely weak. The heli coils will make them stronger than brand new ones.
     
  12. HeadSmess

    HeadSmess Well-Known Member

    just follow the instructions when using helicoils... if you arent confident, experiment on something else instead. i have seen so many multi-cylinder banks destroyed by the amateur use of a helicoil kit... yep, they are cheap compared to a $1000+ cylinder block...until the moron strips them out, retaps to the next size, strips them, helicoils them, plus takes out the cam bearing locating dowels, then ends up drilling right through the thing and wacks a bolt with a nut on the end through the hole... whereas if the same person had used g-clamps, or simply gradually gave each and every bolt a half turn, rather than try tightening each one individually... would have been no issue for us when we went to work on it after my friend bought it!


    sorry, i digress....

    could always just drill side on into the case with a 3-4mm drill, so you go through the stud itself, then hammer in a small piece of steel bar... pin it in place :)
     
  13. dotcom

    dotcom Member

    I got the kit in the mail today and will likely try and fix it tomorrow but I was wondering if since I also have a 6mm stud hole stripped would I need the 6mm x 1 kit or the 6mm x 1.25 kit ? Noticed for the 8mm kit that I got today, it was 8mm x 1.25 so im wondering if the 6mm needs to also be 6mm x 1.25 or just 6mm x 1 ?
     
  14. HeadSmess

    HeadSmess Well-Known Member

    standard M6 is 1mm pitch.

    never heard of a M6x1.25 . doesnt mean it doesnt exist, but usually "special" threads are finer, rather than coarser than the standard...

    keep the helicoil kit together! do not mix the tap up with any other taps you happen to collect! its a special size.
     
    dotcom likes this.
  15. dotcom

    dotcom Member

    A drill bit did not come with my kit or a size specified.
    anyone know the size of the drill bit that I need for the 8mm head bolt stud holes.?
     
  16. bakaneko

    bakaneko Active Member

    Okay, I am back. I actually had the same problem as you again with all my bolts because I really use my engine. This is for others that will eventually have the problem of a stripped bolt hole and might stumble upon this thread.

    Here are solutions to this problem and some are remarkably cheap. Video starts at 0:45



    I went with aluminium foil and bought 4 new 8mm 1.25 hex bolts. I put a good long toothpick size piece all the way into the holes to do this. I didn't use the acorn nut because even that was stripped and you have a higher risk of shearing off the bolt if you tighten too hard. The results is that the bolts are in there really tight and I feel with more pound pressure than I was able to do before with the acorn nuts.
     
  17. dotcom

    dotcom Member

    I actually did find the size
     
  18. HeadSmess

    HeadSmess Well-Known Member

    and what was it?

    normally, you subtract the pitch from the diameter to get the tapping size(80% depth thread... 100% thread is a nightmare to tap, and only 10% stronger), but obviously helicoils need a larger tap, hence drill...

    just for future reference... the size would be a nice thing to mention ;)
     
  19. dotcom

    dotcom Member

    8.3mm = 21/64 is what was on the packaging. Just a bit hard to find. Mission complete too and stud hole is fixed with the helicoil. A bit crooked but I am lucky to be able to keep using the motor. Crooked because I did not have the proper tools necessary to drive the tap down properly but not so bad so I can bend it with force to fit in the cylinder.
    So the 8mm tap and helicoil kit total cost me about $20 with 12 extra helicoils. Now just ordered a 6mm helicoil kit for $12 dlvd which comes with 25 helicoils. Onward and upward
     
    KenM likes this.
  20. butre

    butre Well-Known Member

    I don't bother reading the size, I just grab whatever drill from my index is recently sharpened and about the right size. say for a half inch threaded hole I'll grab my easy to find and always sharp 13/32 bit, or for a quarter inch I'll usually grab a 7/32 bit if I can find the damn thing (I make a lot of quarter inch threaded holes and have a bad habit of not putting things away).

    it's not that much harder to tap 100% thread if you don't try to monkey it all in one go, just peck tap it with a spiral flute tap.
     
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