Best way to fix suptertrapp exhaust/how do these things work?

[sam000lee]

I grabbed this sick 2-1 for my GS450/500 project, weighs about as much as much as ONE of the stock headers and comes with a banged up supertrapp muffler. I'm not sure if the whole system is Suppertrapp or not as was described in the ebay ad, but the header isn't a MAC and I haven't really seen many other 2-1's for the GS450.

Anyway, I'm still figuring out where this project is going and whether I should try to make the muffler work or go with something else. I did some internetting and learned about the supertrapp discs and cores. Does anybody have experiences with these and how I go about matching a disc setup/core to the muffler if I don't know the model?

Also if anybody has any good tips for rounding this thing out before I just have at it, I'd love to hear them.

[sam000lee]

Oops somehow this ended up in the wrong section! Could a mod move it to exhaust or performance section if you see this!

[chuck hahn]

Look at the top tool bar for ADMINISTRATIVE. I think that as the original poster youll get an option to move thread. As for the can..I think youve got a pile of junk and will need to find a used one by placing an add in the PARTS WANTED section and doing some Ebay searches.

[Chuck78]

That's a sweet score there...
Too bad the muffler was so hammered.

If you were able to get it round again, the disc part could just be purchased based on the inside diameter of the muffler can. You basically just add or remove disks to your desired taste. The more discs, the more gaps there are, therefore the more free flowing and the louder. Fewer discs, less flow, quieter.

I picked up another oddball 2 into 1 off of a GS twin in the junkyard, it was in similar condition, except the muffler was missing, and it had some piece of trash universal muffler very poorly welded to it. Luckily that also means it was very easy to remove. I picked up a few different mid pipes at various junk yards that will help me mount a kerker system K aluminum Muffler to it or some other aluminum F1R unknown junkyard mufflers. They are really awesome looking but I have a dual exhaust L&R set, too bad my original gs425 head pipes are not in good shape at all. The right pipe comes down at an abrupt angle towards the left, and then kinks back toward the right, in an effort to make the length of both pipes the same for even flow and pulse tuning. $20 score, well worth it! I also got an almost new 450 Mac system, but I never really am excited to use Mac Mufflers, just the headers. So I picked up a 2nd Kerker System K aluminum can!

I plan to eventually pick up a cheap GS400X, or a B/C model, and build a more budget version of what I'm doing with the GS425, but with 2 off the shelf Wiseco K844 pistons for 449cc 10.5:1. I'm very excited about the little zippy twin build... getting the head ported, and boring it out to at least 489cc...GR650 Tempter cams (hollow cores, .364" lift, 268 degrees duration... very nice! Great street cams! The 500 cams always sound like a pain in the butt because they are designed for spring shim washers to take out the side to side play. I can't remember the exact details of what modifications or machine work are required to successfully run these on an older GS

[Steve]

You might take it to a muffler shop to see if their expander will fit it and get it back to something close to "round".

After it's close, you might be able to use hammer and dolly to fine-tune the shape.

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[Chuck78]

You might take it to a muffler shop to see if their expander will fit it and get it back to something close to "round".

After it's close, you might be able to use hammer and dolly to fine-tune the shape.

^ ^ ^ That's a brilliant idea, Steve!

[Steve]

Thanks. Sort of got the idea while visiting a shop to have a couple of pieces cut to replace a rusted-out crossover on an 850. Unless you have had an 850, you might not know that the crossover is a couple of pieces of stamped steel, not heavy-walled pipe like all the others. The thinner steel is prone to rusting, leaving holes that can't be patched. The easiest way to fix is to replace the crossover piece with two straight pipes. If you expand one end, it can be installed with all stock parts. I watched them put the pipe on an expander, and spread it large enough to work. Last night, I thought "why not use the expander to simply straighten out the muffler can?"

Certainly you have noticed by now that the collective wisdom and overall knowledge of this forum comes from some rather varied experiences. And the willingness to share is what makes this forum so great.

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[thebrandonbeezy]

You might take it to a muffler shop to see if their expander will fit it and get it back to something close to "round".

After it's close, you might be able to use hammer and dolly to fine-tune the shape.

.

Probably going to to that to my v&h cause the end is bent in.. great idea

[Buffalo Bill]

A month old thread but that kind of damage just needs some DIY blacksmithing. Figuring out a makeshift anvil and a heavy hammer.

[80GS850GBob]

I had supertrapps slip ons on my FJ1100 and the muffler you have there seems to be missing the end completely...if I compared it from memory to my old set up. There should be a round end plate to attach the diffusers to and I don't see that...almost looks like someone cut it off.
I'd suggest looking for another muffler that would fit onto the given pipe you have....might be cheaper and less work. {imho}

[GS1150Pilot]

As I've mentioned, I think I have one such.