Exhaust hole - patching up - 1980 GS550L

[ReedSupport]

Hiya chaps.

My beloved GS550L right side exhaust (still looking for a replacement part, asnwers on a postcard please!) has a big hole in it. The previous owner patched it up with something that looks remarkably like elastoplast, but this is not a long-term solution.

I'm on the lookout for a replacement part, and if the worst comes to the worst I'll buy a new 4-1 replacement (and ruin the symmetric exhaust looks of the 550L), but for the moment I'm willing to consider short-term solutions.

So, how do people think I could go about patching it up? The hole in on the underside about a fott and a half from the end of the can (i.e. where the exhaust gas actually comes out of when running). I'm willing to consider shaping aluminium and even welding it on, if needs be, but I'd rather get some kind of clamp or the like.

[salty_monk]

YOu could probably weld it if you're good & the pipes not too thin.
If it's a biggun you're going to need a plate.

A very temporary fix is to get a Tin can, cut a patch out of it, layer the back with firegum & fix it on with a couple of jubilee clips or exhaust clamps.

A steel patch will last longer than Aluminium.

Dan

[Boondocks]

I had a 1969 Honda CB450 that I bought new. It eventually developed a hole in the left muffler, making it loud and ratty sounding. I made a temporary fix using the circular end of a can. I drilled holes through the canpatch and muffler and fastened it using a pop rivet tool. The results were extra slick, with the normal quiet sound resumed with no leakage. The appearance of the can end wasn't all that noticeable unless you were looking for it. The pop rivet tool made a clean, tight connection from the inside out, with no mess or chance of coming loose like an adhesive.

I used it this way for quite a while with no problems, and eventually replaced the mufflers with good used ones. I sold the bike in 1976 with over 20,000 miles on it and it still looked like new.

[salty_monk]

I've done that before on a Kit car to turn it into a "re-packable" type exhaust can (Cut a window & plated it). I didn't think of it before.

For a really good seal use Fireproof Silicon behind it before you rivet. It worked pretty good, I did a few thousand miles like that. It was a 4-1 system with only one can.

Dan

[ReedSupport]

Rivetting a piece of shaped metal over the hole sounds like a winner. What do you think about putting some firegum around the hole before rivetting the new piece over the top? I'm thinking it might help create a seal.

The only question, then, is what to make the piece of shaped metal from. Let's say I'm not equipped to take a piece of steel deck plating and cut and shape it. I'm hesitant about simply taking a sheet of something and hammering it into shape on the exhaust itself, for fear of hammering thee crap out of the exhaust - it's in bad enough shape as it is!

[ReedSupport]

I went out this morning and took some pictures of the hole for dimensions. It's about 2.5 cm by 3cm.

Obviously I took the remains of the previous patch off. I turned the engine over with the exhuast hole uncovered. The only thing I noticed was some kind of liquid popping at the end of the exhaust after a short time. Looked like water - can I assume it was taken up through the hole whilst the bike was running cold, and then started popping when the engine warmed up a bit?

Many thanks for all your help, by the way - I've very little mechanical experience with motorbikes and I'm learning as I fiddle.

[salty_monk]

You'll probably need a big "ish" patch in order to find good metal to rivet into. Don't use Firegum, use Silicon, the fireproof stuff would be best (for installing fire door frames etc).

As far as shaping it, you could do worse than using a tin can, most of the shape will already be there....

Dan