Arc Welding on engine muffler area?

Discussion in 'Motorized Bicycle General Discussion' started by Moisstink, Jun 15, 2014.

  1. Moisstink

    Moisstink New Member

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    I have an issue where my muffler keeps falling off. I was thinking of arc welding the muffler to the engine but wanted to know if this will damage the magneto. The threads are going inside and wanted to stay away from jb weld if possible so I can upgrade the muffler in the future. Any thoughts?
     
  2. FFV8

    FFV8 New Member

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    Is this a Briggs with a threaded exhaust port?
     
  3. 2door

    2door Moderator
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    Is this a Chinese 2 stroke engine?

    Tom
     
  4. turnofftheradio

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    make sure the path goes to ground lead on your welder first, clamp it to the exhaust, not the frame. If you are stick welding, you are brave. I did mine with 308l-16. that muffler is really, really really, thin stuff.

    On second thought, I think I mis read your post. Are you trying to weld a muffler right to your engine? this must not be a china 2 stroke?
     
    #4 turnofftheradio, Jun 16, 2014
    Last edited: Jun 16, 2014
  5. Davezilla

    Davezilla New Member

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    I wouldn't weld anything directly to the engine... get yourself some self locking nuts, not the ones with the plastic inserts, but the all metal self locking nuts and problem solved.

    Now if you're just trying to weld the muffler to the pipe or something like that, it's not easy as the metal is very thin but brazing it will hold up just fine, I've brazed pipes together on my Buell with no issues before.

    If you're trying to stick weld it, you'll need to use a 1/16" rod but that may even be too much as the amperage will need to be set really low and the rod will tend to stick to the metal before getting a good arc started, but if you turn it up enough to not stick to the metal you'll risk blowing holes in it. You might get away with oxy acetlyne gas welding it or Mig/Tig but beware of teh really thin and cheap metal these are made of.
     
  6. Moisstink

    Moisstink New Member

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    I was going to arc weld the muffler flange directly to the engine on a china girl engine (just some tack welds). The threads inside the engine are next to gone and it is difficult to keep them tightened. I was going to use some red lock tight or jb weld but need to remove the bolts once I get my new muffler. Thanks for all the responses. I picked up a tap and die set from harbor freight, got it home and realized it is good for nothing really.
     
  7. MEASURE TWICE

    MEASURE TWICE Active Member

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    If there is enough material left then, look up Helicoil.

    You do it or a machine shop. If you do it then have the special size drill and tap for the Helicoil. Insert tool and tang breakoff tool can be improvised to save money.

    Individual parts I can get a a supplier in San Jose, CA so I never spent for a whole kit setting you back a bundle.

    MT
     
  8. Davezilla

    Davezilla New Member

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    You got a tap and die set? ... Why not just drill the holes the next size up and re tap them to take some M8x1.25 bolts. You'll just need to google "tap drill chart" to find out what bit you'll need to drill out the holes with, then cut the new threads with the tap and use the larger bolts or even better, studs. You may need to drill the holes in the new exhaust flange so the larger studs can go thru, but the repair would be permanent and last the life of that cylinder.

    The main reason I'm even talking about up drilling and re tapping is because you got the kit, and helicoil kits can get real expensive real fast... enough to exceed the value of the cylinder so unless you got some serious porting work done or just don't want to break in a new cylinder and set of rings, it could be cheaper to just replace the jug and install a new set of rings. but since you got a tap and die set, you could just up size the threads and it'll be good to go again, just make sure you use the right drill bit size and keep it well lubed while tapping, and take your time tapping cutting one or 2 new threads then bringing it back out several times until you reach the botom to prevent the tap from loading up and getting stuck, anytime the tap feels like it's taking extra force to turn, back it out, it should go in with moderate force, but not excessive like it feels like it wants to lock up.
     
  9. curtisfox

    curtisfox Well-Known Member

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    Agreed studs would be best lock tight them in. I was jut looking in farm store a couple days ago and they sell tap and bit together. Also the next best size may be standard sometimes they are in between, need to measure.......another is the head is aluminum and the flange is more likely steel and you can't weld the two together............Curt
     
  10. CTripps

    CTripps Active Member

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    You're better off following the advice above.

    Trying to weld the low quality steel muffler to the low grade aluminum the jug is cast from is almost guaranteed not to work. An arc hot enough to weld the muffler material will create a puddle of liquid aluminum between your feet.
     
  11. mapbike

    mapbike Active Member

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    You cant weld Steel to China-Lume ( aluminum of any type for that matter... you cant weld an allow to steel unless the steel has a heavy zinc plateing and then there is a way to torch weld the aluminum to the steel that is zinc plated but it isn't very strong, I've done that before just messing around. again you cant arc weld steel to aluminum period..... dont try it or you will ruin the jug on your engine, a new jug is only $23 or so, so if it does get ruined its a cheap quick replacement fix.

    http://www.ebay.com/itm/190933567981?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

    or the whole shooting match for $42 shipped to rebuild the entire top end.
    http://www.ebay.com/itm/191036700418?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

    Take the advice from others here and either heli coil the thread holes or just drill and retap them for the next metric size bolt which will be M8x1.25 or if you want to really keep it simple, you can tap the holes for a 1/4-20 US thread and use 1/4-20 studs, I have done that on engine mounting holes that got wallerd out, I use Red Loctite on the studs instead of the Blue lately, the red will still come loose but it holds much better than the Blue and I have yet to need heat to get the studs loose when secured with the red loctite.

    I also double nut the exhaust studs instead of just using lock nuts, double nutting them adds a big extra lever of security and they will NOT come loose if done properly period.

    Map
     
    #11 mapbike, Jun 17, 2014
    Last edited: Jun 17, 2014

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