[FriedrichOdermann]

Hello all, I have an exhaust leak I BELIEVE. I have a video here of the leak, it's coming from the exhaust connection beneath the motorcycle (1980 Suzuki GS550L). I don't think it's oil based on where the leak is coming from and what the fluid looks like but it's definitely not water/condensation. Looking for some ideas on how to fix it. It leaks the most when it's idling in neutral from what I've found.

The picture of the exhaust attached is what the exhaust looks like on my bike and the leak is coming from that center connector.

(The video may not have uploaded...but I tried)

 

[Retired Guy]

I've seen holes made by the factory in exhaust pipes, at the low point, so water wouldn't condense in a pipe, collect in the low point and rust out the pipe.

If you're concerned about some kind of "yuck" coming out, it could be carbon from the burnt gases mixing with water that has condensed in the pipe.

When you ride, are you riding long enough to get the engine thoroughly warmed up, or just short distances and then shut it off? It will make a difference.

 

[FriedrichOdermann]

Usually I turn the bike on and let it idle as I put my helmet and my gloves on so that it warms up a bit. Then I will ride it probably ten to 20 minutes to a different location and shut it off. Probably getting up to 50-60mph.

 

[Retired Guy]

Start taking the twenty minute (30 would be better) route for a while, see if anything changes. Also, I don't see what part of the country you're from but could a damp climate be contributing?

 

[FriedrichOdermann]

I'm in Minnesota, it's been raining a bit recently but it's not humid at all.

 

[Retired Guy]

Isn't that the "Land Of 10,000 Lakes"? Just kidding. The whole thing just narrows down to avoiding water condensation inside the exhaust pipes as much as possible.

Water will also condense inside your engine, so getting your engine up to operating temperature and keeping it there long enough to turn that water to steam, so it can be vented off.

Got to get the pipes hot too.

I believe this was covered in a Motorcyclist magazine article i read years ago. You'll be getting more replies shortly and maybe some more up to date info.

 

[Retired Guy]

Oh, if that leak is at a joint with a clamp on it, take it apart, clean it all up, wrap some muffler tape around the joint, (cut to size of course) two or three wraps, (whatever you can get under the clamp) then tighten the clamp. That should stop any leak.

 

[WintrSol]

Oh, if that leak is at a joint with a clamp on it, take it apart, clean it all up, wrap some muffler tape around the joint, (cut to size of course) two or three wraps, (whatever you can get under the clamp) then tighten the clamp. That should stop any leak.

Or, if there is no clearance for the wrap, a thick coating of the copper-colored high-temp RTV should do it. Let it set overnight before riding, or it may blow out.

 

[FriedrichOdermann]

I feel like there shouldn't be that much fuel in the exhaust though. I checked the air filter to see if maybe it was clogged causing the motor to run rich and the air filter is completely black. It doesn't look like your typical air filter though. More like a sponge. It's so black though that it looks like it's just always been black. Any chance the filter was black off the production line?

There was also some fuel soaked into the spongey filter. It's been cruising through fuel also so I need to go buy some and fill it up before I try running it again.

 

[WintrSol]

It may be an oiled filter, and also may need cleaning and re-oiling. Take the spark plugs out - they will say if you are really rich.

 

[SemiFast]

I feel like there shouldn't be that much fuel in the exhaust though. I checked the air filter to see if maybe it was clogged causing the motor to run rich and the air filter is completely black. It doesn't look like your typical air filter though. More like a sponge. It's so black though that it looks like it's just always been black. Any chance the filter was black off the production line?

There was also some fuel soaked into the spongey filter. It's been cruising through fuel also so I need to go buy some and fill it up before I try running it again.

If there is enough raw fuel in the exhaust system that liquid drips, or leaks, from a pipe connection then I'm thinking maybe there is a flooding condition happening in the carb's.
The spark plugs should show black rich if that's happening.
Along the same lines, you might want to check the crankcase for fuel contamination.

 

[FriedrichOdermann]

I'll check the spark plugs today, thank you. I'm planning on installing velocity stacks anyway so I'm not sure if I even want to put the filter back in because the whole air box is coming out in a few days once the stacks get here. Then I'll readjust the air/fuel mixture in the carb and I'm hoping that fixes my problem.

Just a side note. The apparatus that holds the air filter "sponge" is still in the air box, I only removed the sponge. What would be the damage of running the bike without the filter (sponge)? The aparatus still has a wire filter built into it and I figure all the twists and turns the air needs to make to enter the air box and then into the carb with the wire mesh will act as a pretty good barrier to dust/particulate entrances. Also I don't see how it could give any LESS protection than velocity stacks, which only have a wire mesh filter and offer even less barriers to entry for the air.

 

[Unkle Krusty]

On the road race bikes, we did not run filters. But we had them apart on a regular basis, and there was little dust.
Many of the off road bikes use oiled foam filters. That is what I use on my 83 XS400. There is filter oil available. Also cleaning instructions on line. Not a big job, and for pavement riding can be done every six months. After every cross country race for the off road bikes. Some bikes like my XS400, with the stock air box, run different size main jets. This is because the air box has to allow room for the battery. I rearranged the air box to only hold the battery, and then switched to the foam filters, and main jets of the same size. Which BTW were the same as the smaller one as stock.

The 400 is a twin and has a cross over pipe. It rusted out. I did some research on cross over pipes, and decide to maintain it, by using a flexible pipe. It rusted out in about a year. Today I wrapped it and we are quiet again. Next time the cross over pipe fails, I will eliminate it, by blocking the exits from the main pipes.

We did not run any cross over pipes on the rave bikes, and it seemed to work well. I ran more horsepower on a 750 Norton than the smart guys are making today, with better push rod motors like the Westlake.

I have also considered making a 2 into 1 set of pipes. I use cheap after market mufflers, and they seem to work.

If my approach to this bike sounds cheap, you are correct. However, none of the newer 400 cc bikes perform any better.

UK