Exhaust Suggestions for loose exhaust studs/bolts

Discussion in '2-Stroke Engines' started by StrontiumEthics, Jul 28, 2010.

  1. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    My exhaust studs on my engine keeps coming loose, its the second time after i tightened it. I don't want to over tighten the cheap Chinese studs in the block because I don't want to strip it. I was thinking of cutting a grade 8.8 automotive M6 bolt and using that as the two exhaust studs. But I am wondering what kind of nuts I should use. After using lock washers, and watching the Bolt Science video posted by pucksterpete, I dont know what else I should trust! lol. I was thinking Nylon but I maybe the heat might tamper with it.

  2. GearNut

    GearNut Active Member

    You could always drill a hole through the portion of the studs that extends past the nuts holding the exhaust on and then safety wire the studs together. It would not have to be wired tightly at all, and a bow in the wire to clear the exhaust pipe would be quite acceptable, just twist the 2 strands around each other. Safety wire in this type of application would not need to be strung tight to do it's job. The studs would be prevented from unscrewing out of the cylinder, and the nuts would be prevented from unscrewing past the safety wire (like a cotter pin application).
  3. motorpsycho

    motorpsycho Active Member

    oh man...come on!
    take out the junk chinese studs as long as they're loose, and put in some good quality studs using loc-tite to keep them tight in the block. use flat washers, lock washers and standard nuts with loc-tite.
  4. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Oh ok. That sounds like a great idea! But what about the Nylon nuts? I have a couple of them now. Wondering if the heat will mess them up?or perhaps make them better with Loctite?
  5. Fulltimer

    Fulltimer Member

    The nylon would probably melt.

  6. kerf

    kerf Guest

    How about a star lock washer with your studs? Will Loctite even stand up to the exhaust temps?
  7. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    This is the exact thought process im going threw! lol i was thinking of Loctite but what about heat from exhaust.
  8. andreasklapp

    andreasklapp New Member

    you can get high heat loctite. you can also use a sort of washer with two arms on it, one folds over the nut to prevent it from turning, the other over your manifold. i don't know exactly what your setup looks like, but my ford v8 has something similar on it, and i used to use the same things on skateboards to keep them from going loose.
  9. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    EUREKA!! I found out why my bolts are getting so darn loose. It has to do with the Muffler. There are 2 kinds of mufflers. One type has a Long M6 stud going through the center bolted onto a the muffler Cap, the other has 2 very small bolts bolted through the muffler and cap to keep the cap on. I have the one with the long M6 stud going through the middle. When the M6 bolt holding the cap gets loose it VIBRATES LIKE ****, which is where Im getting some of the vibration from, possibly loosening the Exhaust nuts! Tell me what you guys think of that, and a possible solution.
  10. GearNut

    GearNut Active Member

    That very well could be causing enough vibration to loosen up the mounting nuts at the cylinder head. Solution? I would run a castellated nut and a cotter pin.
  11. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Before I use the cotter pin idea, im going to Loctite the **** out of all these parts. I just removed the muffler and applied a good amount of loctite. I also loctite the nuts that fasten the muffler to the head along with Loctite in the cylinder head.
  12. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Now a quick question. Exactly how hot do these engines get after some time of running?
  13. motorpsycho

    motorpsycho Active Member

    I would chuck that muffler and get an expansion chamber, but that's just me.
    Last edited: Jul 29, 2010
  14. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    You know its funny that you mentioned that. I have a sick bike parts expansion chamber but I have to get some new copper couplings and elbow. I had a difficult time mounting it onto my bike the last time. I might just give it a try If this doesn't work.
  15. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Anyone know how hot these engines get?
  16. Skyliner70cc

    Skyliner70cc Active Member

    Have you considered going electric or a more reliable gas engine system? It seems like you've been having a lot of issues with HT engines and spend more time fixing and posting then riding.

    You want to keep the engine's head temperature between 225 and 250 deg F. Other parts of the engine such as the exhaust are probably much hotter.

    I use loctite and nylon fastening nuts on my exhaust. The nylon melts and holds the bolt just fine. I, of course, double nut almost every stud.
    Last edited: Jul 29, 2010
  17. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Yes I considered it. But I have a lot of fun with them = ). I like to figure out and solve problems, I don't mind it. Every time I make a build, I get less and less problems, so I feel better. I plan to get a four stroke engine soon. But I don't really have the money for it, and I like the 2 strokes better. Playing with these engines really increases my mechanical aptitude. I'm only 17 so its cool.
    Caplain likes this.
  18. StrontiumEthics

    StrontiumEthics Motored Bikes Sponsor

    Today I just installed the SBP Expansion chamber I had laying around that I forgot about. Performance increase was excellent. Its better than that stock exhaust. I cant believe i forgot about it. lol. Thanks for the suggestions guys.
  19. louishb50cc

    louishb50cc New Member

    loose exhaust

    I just Got some nylock nuts some new m6 thread. And made an exhaust support out of some thick wire i found in my shed.
  20. 5-7HEAVEN

    5-7HEAVEN Guest

    How about "lock washer-nut-lock washer-nut" on each stud?:idea: