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Discussion Starter · #1 ·
On my 1980 GS550L, there is a rust hole on the bottom side of the right exhaust right before the baffle. It's probably two inches long by 1/2 inch at it's widest point. Would this affect idle and cause it to run differently or is it purely a sound issue? :-?
 

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Is there actually an exhaust leak at that point; that is, are hot gasses escaping ??
Given the size, probably so but had to ask.
If it has an impact on how the bike runs it probably isn't much.
 

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It will absolutely affect the way the bike runs. By having a hole upstream from the baffles you have in effect created an open exhaust, and changing to an aftermarket open exhaust will almost always mean you have to change the carb jetting. Worse, you have an open exhaust on only one side of the dual exhaust, which is not good for an engine at all. Replace the exhaust or see if someone will weld a patch over it for you.
 

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Discussion Starter · #6 ·
I may do that, DrBob. Obviously it's quite loud being that I have to run with the choke on a bit (working on that issue).

Here are it's issues in full:
1. Must run with the choke half open or it will stall. It idles at about 1000-1200 RPM once warm with it open halfway. To start on cold days, I have to spray a bit of starter fluid into the intake. Even then, sometime it doesn't start right away and may take several attempts. Most likely a carb cleaning is due.
2. It's very loud. Most likely due to the exhaust hole.
3. I only get about 30mpg in it. Possibly due to the choke issue above.
4. When riding, it doesn't run smooth. e.g. At 40mph with steady throttle, it revs up and down like it's sucking in more air into the intake in spurts. Possible vacuum leak on the carbs.
 

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You have only one problem: the bike is running lean from the exhaust leak. This lean condition causes hard starting, poor mpg, poor throttle response, and a lean surge. Pulling the choke out makes the mixture richer, which is why the bike runs better wheb you pull it out. A lean condition will also cause the engine to run hot, causing damage to the plugs, valves, pistins, etc. So you REALLY need to fix the exhaust leak.
 

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So you REALLY need to fix the exhaust leak.
And STOP riding it when it runs like crap.
One side probably is lean due to the exhaust problem.
"fixing" that with the choke causes the other side to run rich, possibly fouling the plug and if done long enough, maybe even damaging the rings.
 

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Discussion Starter · #11 ·
I didn't ride today and will be fixing it tomorrow. I'm still searching for a replacement exhaust on the right side. Any good parts locations in GA? I will use a temp fix or have it welded in the meantime.
 

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I'm still searching for a replacement exhaust on the right side. Any good parts locations in GA? I will use a temp fix or have it welded in the meantime.
Unless the left side looks to be MUCH newer than the left, you probably should look for both sides.
Call a salvage yard in your neighborhood. If that one doesn't deal in bike parts, they probably can tell you who DOES.
Maybe DrBob can help with what years would be compatible.
 

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Discussion Starter · #15 ·
OK. I've searched eBay to no avail and Steve's Cycle Salvage won't respond to my requests. If I purchase aftermarket exhausts for it, I'll have to do something to the carbs, correct?
 

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If I purchase aftermarket exhausts for it, I'll have to do something to the carbs, correct?
No......not if you get pipes with REAL mufflers on them.

Might be kind of hard to find and when they say "baffles included" that's mostly a lie and it will still be LOUD.

I had a Honda 550 and got some pipes from JC Whitney. They were good enough......AFTER I got some fiberglass and turned the baffles into a real muffler.
 

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Discussion Starter · #17 ·
Does anyone know what years and models of Suzuki also use the same exhaust as the 1980 GS550L? It appears to me that many bikes of those years use the same exhaust just by looks.
 

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The production run was from 1979 to 1986, and the L model basically stays the same size throughout those years. (they did not make an "L" in 1981, according to the model history page on suzukicycles.com)
I'm no mechanic, but I assume there could be changes to the exhaust system when the size of the bike changes... hopefully someone with more direct knowledge of this product line can give you more specifics.
 

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Discussion Starter · #20 ·
OK. I cannot seem to locate any stock pipes for this bike. My thought is this: Maybe I should remove the pipes, clean them thoroughly, repatch the rust holes with muffler patch, wrap them in exhaust wrap. Next, I would need to find a way to repack the mufflers as they are horribly loud. Has anyone done this on an old bike and can you provide some advice?

The other option would be to buy a couple new mufflers, mount them and have the carbs jetted and synced.
 
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