Topic: Hole in Stock Muffler

[ct_racer]

I have a 79 (I know, I know, I know...  technically the wrong boards, but i used to own a 73 500 and i've grown to like it here) with a stock exhaust.  The right lower muffler has a decent sized hole in it on the bottom near the header.  Other than that hole though the exhaust isn't perfect but is in pretty good shape and still looks nice.

I'm having a hard time finding a replacement, and I'd really like to keep the stock 4-4s.  I stopped by a muffler shop yesterday to try to see if they'd weld a patch over it, but the guy told me the material was too thin and he'd just end up burning through it.  He also said that even if it was welded it would rust through again fairly quickly.

I'm wondering what you guys might have done with a problem like this, or if you have any other recommendations.  I tried a wrap that is supposed to seal itself with the heat from the exhaust, but I couldn't get it to seal real well and it just fell off after a few minutes.  Unfortunately it's not exactly running the best with the hole and ran amazingly better while the wrap was on.

[grcamna2]

I wouldn't listen to those folks w/ "it's too thin of metal to weld"  I've brazed some mufflers before w/ non-galvanized sheet metal of about the same thickness as the original muffler and it worked out excellent all the way around.Make sure to clean up the muffler hole area real well & then grind it up there to make the steel rough & get the chrome off.
It'll run terrific when they're patched solidly;let us know how it turned out.

[ct_racer]

That's kind of what I thought.  I think the hard part will be finding a shop that will to the welding for me.  Perhaps if I do the prep work myself it will be easier to find one.  I've welded to thin steel before (disc brake mounting tabs to an old schwinn frame and fork).  I only did the prep work for that though as I can't weld.  My buddy who can weld is several hours away and it's a pain for him to do it.

Do you recall what gauge steel you used?  And, did you do anything to keep it from rusting that won't just burn off?  Ideally I'd like to not paint it, unless I cover it with clear and can find that in a hi-temp...

[grcamna2]

I just went to a sheet metal shop and found some decent gauge steel.I then cut it out to the size I thought was good & either had it brazed or tig(more expensive)welded.I do braze,it isn't too tough;if you've soldered before it's the same.Heat it all up until it's red & then puddle the brass brazing rod into the spaces that it needs it.
I think you should find a friendly muffler shop & see if one of the workers will possibly either braze or mig weld(ask him to use low heat)it.

[Stev-o]

I bought a 550 that had a patch welded on.  Didn't look good but it is possible.
Find someone else, go to a small shop that will weld anything.

BTW - you are always welcome here.  I post my non-SOHC threads in the "other bikes" section.

[grcamna2]

I've worked on customers cycles;I patched & saved a good number of exhaust systems.It's best to lightly clamp the patch down w/ welders Visegrip clamps or have a friend hold it so it doesn't protrude too far away from the muffler.

             Happy patching 

[ct_racer]

BTW - you are always welcome here.  I post my non-SOHC threads in the "other bikes" section.

Thanks, I did the whole cafe thing with my 500...  and then it was stolen.  I guess this is why I can't have nice things.  The 750 I just picked up though is already in pretty good shape, though it isn't perfect.  Some of the chrome will get a little screwed up obviously, but it shouldn't be too visible.  I also found a "flame proof" clear coat that should hopefully keep more rust off the outside of the pipe.  Don' know if you've used it but I'm thinking it couldn't hurt... (http://www.amazon.com/Satin-EXHAUST-Clear-Coat-High/dp/B0082LGJ2C)

I don't really want to do anything to it performance wise and while I was thinking of dressing it up a little sportier, it's so damn comfortable as is that I'm really thinking of just leaving it as is.  I have only tried one shop so far so hopefully I an find something else close by, but most shops by me are national or regional chain type things.  It's times like this that I wish I could weld myself.

I think in the mean time I will do the beer can and hose clamp thing until I can find a shop willing to take on the job.  It still wont be perfect, but it should run a hell of a lot better than having a hole on the backside of the header.  I tried some patch tape that fell right off as a temp fix, but while it was on I couldn't believe how much better it ran, and it already runs pretty damn good.

[grcamna2]

I looked at that Flameproof High Heat paint,didn't know they made clear;I've used the High Heat silver before & it wasn't too bad in small spots.I'd spray some into the cap & then use a small artist brush to apply it.

[Stev-o]

Doubt that clear coat would help, mufflers usually start rusting on the inside from condensation.

Head to the "east side" of town to find a small welding/muffler shop. I had a mounting bracket welded on my Kerker muffler, guy charged me $20, was totally happy with that. Did it quick while I waited and supervised.

[ct_racer]

As far as the rust from the inside out is concerned, I am considering storing it with a tank of 75:1 2-stroke.  The tank has some rust so I want to do an acid bath to clean that up, and am thinking a nice oil sheen on the tank.  Then come spring time that sheen should make its way to the exhaust as well.  I had read about doing this somewhere, but haven't done a ton of research on it.  This obviously isn't conventional, but conventional is typically ending up with holes in the exhaust and replacing it.