Stripped threads!

Discussion in 'General Questions' started by SEGACDX, Nov 20, 2013.


    SEGACDX Member

    Well I guess I should just invest in higher quality parts!

    So I has cleaning my piston and cylinder head out and when I went to put the intake pipe on the thread on the screw in the cylinder head striped!

    So I did a quick fix of using Teflon tape and a lot of it.

    So what do I do buy a tap kit or get a new cylinder had or even a new kit for parts?

    I should add the motor it running much better other than that.

  2. bigbikeseat

    bigbikeseat Member

    Install a helicoil. Make sure that you drill the hole at a perfect 90 degrees from the surface. A drill press or a hand drill guide will do. A drill guide can be made from a brass tube so that the drill spins inside the tube with no play.. Then the brass tube is soldered or brazed to a washer at a perfect 90 degree angle. The drill guide is then held against the hole to be drilled. The helicoil is a strong thread fix, and after installing it the fix will be permanent.
  3. crassius

    crassius Well-Known Member

    assuming you meant the exhaust stud on the cylinder, you might be OK with a higher grade stud screwed in really tight - these often get stripped because the muffler hanger isn't tight enough to support the weight of the muffler so that it vibrates and pulls on the studs

    I'd try an 8.8 or 10.9 grade in there and make sure it is supported by the hanger to see if that will hold it.

    SEGACDX Member

    At some point I need to have a hangar for the muffler but mine will not reach!

    I would have to make something to replace the stock one.

    But what I should have made clearer was the intake where the carburetor goes it where one of the bolts came out of the cylinder head, I've used some Teflon tape to widen it up and tighten it to stay in place.
  5. IbedaYank

    IbedaYank Member

    helicoil or timesert... proper way to repair stripped threads
  6. HeadSmess

    HeadSmess Well-Known Member

    the problem lies in this... did the cylinder crack around the stud? ive had that happen once or twice. that means new cylinder. or welding and drill/tap. only to have it do it again :jester:

    of course, if its stripped simply because the guy in the factory got over eager and epoxied it in place (seen that more than once too!) youre in luck. maybe.

    being the intake, you cant really tap it out to the next common size up, M8. could maybe squeeze a M7 in there but the extra cost of finding the tap and studs for that size is as much as a new cylinder, and wont necessarily work. 1/4 x 24 could be an option, but i throw things at people that mix up imperial and metric threads. its a nasty habit. dont start up now!

    an M6 helicoil is the easiest method, but....the kit costs about as much as a new cylinder, and getting any workshop other than your friends to do a helicoil, usually, once again...costs more than a new cylinder. though it is a simple five minute job they usually give to the apprentice who has no idea what he is doing... which only makes things worse.

    if you do choose to get a kit, its worthwhile to helicoil the whole engine. the inserts only cost a few cents. its the special sized tap that costs ya! and dont EVER mix that tap up with others if you have any more... anyways. a motorcycle or marine mechanic is more likely to have an M6 kit in stock than an auto mechanic...

    last resort, it does work... ram stud back in hole. get a 3mm drill bit. drill into side of cylinder, where its beefed up for the stud, so you drill through the stud as well. then hammer in a pin of some type.a 1/8 welding rod "butt" is good. lock the stud in permanently :)

    or carefully dremel a slot, enough to get a thin nut in BEHIND where the stud locates...then use a bolt. now thats almost standard on brushcutters/chainsaws. dont even know if that one can be done...just brainstorming....i think im flooded :jester:

    oh! yes! the best method!

    TEKSCREWS! :jester:

    everyone loves tekscrews :)
  7. IbedaYank

    IbedaYank Member


    top is helicoil bottom is a timesrt... now what one will be stronger lock timesert in place with locktite
  8. crassius

    crassius Well-Known Member

    kinda looks like that collar sticking up on the bottom one might interfere with getting intake to seal ??!!??
  9. IbedaYank

    IbedaYank Member

  10. crassius

    crassius Well-Known Member

    ah, I see it now

    SEGACDX Member

    I am just going to buy a new Kit for parts or even just a new cylinder repair kit. I've used some paper and Teflon tape to keep it in place and it is very tight. I think it should hold till I get my new parts. I've looked at some Helicoil Kits online and yea I am not paying 130 bucks upwards for that.
  12. IbedaYank

    IbedaYank Member

    then you REALLY need to learn how to shop,price:1,ppr_max:20
  13. HeadSmess

    HeadSmess Well-Known Member

    first time ill agree with this doofus.

    130 for a FULL set covering M5 to M12 is not necessary! (though i always mean to get one)

    just an M6 kit with the tap, the winding tool, and the inserts...$15 is the cheapest ive seen. $70 for the same thing elsewhere...etc. shop around.

    inserting them is a learning curve for some people... the number of ruined engines ive seen with DIY helicoils... crikey! a racer helicoils everything, because they tear down so often, saves wear and tear on alloy threads.

    a dodgy bast4rd helicoils one or two, then tries tightening each bearing cap individually, just like he did the first time, strips the first lousy helicoil job, taps out to M8, repeats the process, helicoils the M8, ignores that they are bearings and the dowels are there to locate them squarely... drills through into an oil gallery, right through the head and puts a nut on the bolt.... and then the new owner is left to deal with a siezed camshaft and needs a new (hard to find, not to mention pricey) head... ad nauseum.

    hint. dont work on old engines :cry:

    unless its a furin four cylinder :jester:
  14. IbedaYank

    IbedaYank Member

    takes 1 to know one....

    not sure what he is crying about as a timesert kit just for ONE size and one specialized use cost me $400. But now I do not have to pull the cab and front clip off the SWMBO's Fix or repair daily. to the tune of $3500 to havew the heads replaced due to it blowing out a sparkplug.

    If you have the right tools you can fix many problems without paying for new parts and then waiting for them to get there. these motors only use 6mm 1.0 8mm 1.0 and 8mm 1.25 threads for studs and bolts to hold the cases togather and parts to the cases/cylinder

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    Slang. a foolish or inept person.

    being everything I do is well thought out and planned and I can do my own work without somebody else doing it for me I am hardly foolish or inept

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    having or showing no skill; clumsy.
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    clumsy, awkward, maladroit, bungling, blundering;
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    "his mother could pitch a wicked fastball, but she was completely inept in the kitchen"
    antonyms: competent
    Last edited: Nov 25, 2013