Exhaust stripped bolt on exhaust manifold

Discussion in '2-Stroke Engines' started by linnix13, Mar 11, 2009.

  1. linnix13

    linnix13 Banned

    i over tightened the bolt going into my engine. it stripped the female input on the engine. can i put alot of loctite in there or is there a type of industrial sealant or glue i can put in there because if you know what theses HT engines are like its a bolt that goes in thru the ehaust and into the engine block. theres not much of a gap and it almost threads but its just to stripped. thanks and im fine with putting it in and making it permanent because its a threaded rod not a bold, you put the nut on the end after its been threaded into the engine and you put the muffler on. thanks again

  2. cooltoy

    cooltoy Member

    Dundas, Ontario. I'm in Lindsay.
    get another stud and see if there are any threads left in the back of the hole that is striped. I guess you could try a Liquid Metal or JB Weld kind of product. If there are a few threads left and you use a filler of some kind it may work.
    You really should tap some new threads in there but it's up to you.
  3. fenderhole

    fenderhole New Member

    the same thing happened to me. although not the "proper" way to fix it, i just threaded in a slightly larger O.D. stud. worked like a charm. be careful though, you only get one chance doing it this way.
  4. Mountainman

    Mountainman Active Member

    it's what we call a cheap fix !!

    yes this is probably the best repair

    ((( first re-tap ))) to new slightly larger size
    new stud and you should be in

    have used JB weld so as to tighten loose threads
    but -- JB weld used on very hot things -- not to sure

    one can take a slightly stripped item
    put a little JB in the loose now hole
    wrap some thread that is wet with epoxy around bolt threads
    put it in -- not very tight -- epoxy will harden
    it's what we call a cheap fix !!

    ride that thing
  5. arceeguy

    arceeguy Active Member

    A new cylinder is around 20 bucks + shipping, and would be the "right" way to fix the problem IMO.

    I think you jinxed yourself with the "things are going too good" thread. If it ain't broke, don't fix it! As you have found, it is pretty easy to over torque things in aluminum. Be glad you learned this with a $120 bicycle engine, and not an aluminum cylinder head on a car! :)
  6. linnix13

    linnix13 Banned

    ik why did i start this thread! ever since i started it i have blown 2 exhaust gaskets ruptured a fuel line my spark plug tip broke off and now the bolt!!
  7. Mountainman

    Mountainman Active Member

    back when things were going so good !!!

    hang in there
    all these things help with the learning curve

    makes it all better when you ride that thing
  8. emdude

    emdude Member

    Adding to all of the good advice above I would say that the studs that come on the engine are not really a precision piece of metal. They seem a bit wimpy. So if the there is any untouched thread left in the cylinder a new high quality hardened steel allen-head bolt from you local hardware store just may do the trick because there's a chance that the better bolt will partially "recut" the damaged thread. You need to investigate what is left thread wise in the cylinder. If it works I'd replace BOTH sides with a good allen head bolt...looks more better anyway. Yes I did say BOLT and this of course has to be sized up pretty well length wise compared to a stud or threaded rod.

    There is of course the "red neck", and definitely last option of trying the following if none of the above work for you:

    Remove the the metric stud. Size it up to the CLOSEST American standard bolt that is the SMALLEST amount larger than the metric stud but similar in thread pitch. Get this in hardened steel. This just may be what will work if the new slightly larger bolt "cuts" it's own path into the worn out thread.

    I hate to admit it but I've done stuff like this myself....it even worked....sometimes.

    I wonder...is the there enough meat around the area in question for a heli-cal thread insert? Of course the kit for this might cost as much as a new cylinder.
  9. linnix13

    linnix13 Banned

    because i am going to need my bike for the summer i am having it takin into a shop(its actualy in there now) and there doing a heli-cal and there going to replace all the cheap metal with good metal. im also going to get a new gas can(the one i have now requires alot of duct tape to hold the lid on!) and lots of loctite. also how often should i replace my chain? this ones got 2500km on it but its not the one that came with the bike its a higher grade one. oh and btw i like this site alot, the people are friendly and responsive even though im new here. thanks all:grin5:
  10. spad4me

    spad4me Member

    The easy chain mod is to use #41 chain available at Tractor supply, Lowes, Ace .
    You can sometimes use a bmx chain if your front drive sprocket is thin enough.
    I have used both.
    I am currently using a (VERY LARGE) #420 chain as it was the only one in town ( No kidding) when I needed a replacement. LOL
  11. impression

    impression Member

    i done the same as you and ended up getting a new barrel.
  12. Skyliner70cc

    Skyliner70cc Active Member

    I got a new cylinder from a vendor for 8 bucks plus shipping. You can't beat that.
  13. Alson

    Alson Member

    Striped intake bolt hole

    I bought a Time Sert kit to repar my striped hole, cost 60 bucks though, its a good kit but costs, they give you 5 serts with the kit
  14. keatonx

    keatonx Member

    On my homelite weed eater i keep on stripping the carb manifold bolts so I just do what fenderhole does: screw in a bigger bolt. xcept once I was doing this 3 times on the same part of the cylinder and I couldn't get any bigger without making the hole in the manifold bigger, so I filled er up with JB drilled a small pilot hole in it, and screwed my bolt in there. And held great!
  15. midnightrider

    midnightrider New Member

  16. midnightrider

    midnightrider New Member

    Whats an OD stud
  17. KCvale

    KCvale Motorized Bicycle Vendor

    Just because it comes with a stud doesn't mean you have to use one.
    Just find yourself a pair of slightly larger bolts and tap the engine and be done with it forever.
  18. Fabian

    Fabian Well-Known Member

    Using exhaust studs from the word "go" helps significantly.