Plugged Exhaust?

[GGely]

Hi all, on my last ride, I stopped to check my GPS and noticed an exhaust smell while sitting there. Figured it was a gasket letting go so put it out of my mind and got back to riding.

On Thanksgiving Monday, I pulled the ST out and warmed her up. I noticed two things, the first being that puffs of exhaust was coming from what I am pretty sure are the drain holes. in each muffler. The second thing I noticed is that the left muffler had no real output. If I put my hand at the end of the right muffler I can feel and see the exhaust. Left side, not so much.

I used an infrared thermometer to confirm that the 4 cylinders were firing.

I am assuming that there is a blockage of some sort in the left muffler causing the exhaust from that bank to go through the right muffler. I am expecting that there is a crossover between the two exhaust headers just before the mufflers.

Two other points: these are OEM mufflers of unknown age and I have a complete (I think) Delkevic exhaust system hanging on my garage wall. For what it's worth, since I returned to riding I've had a GL650 Interstate and the ST, so I don't have a real idea of how it should perform, sound or handle. Having said that, it pulls hard, sounds great, handles well and is my favourite bike so far.

So, Oh Great Hive, what does your collective wisdom suggest is the cause of my challenge and what do you suggest is my course of action?

 

[gmtech94]

It could be that the left exhaust is full of water on the sidestand and no letting much flow through . If it runs okay check it next time after a long run on the center stand .

 

[GGely]

Thanks for the idea, gmtech94. When I checked it Monday, it was on the side stand. I'll hopefully be out on it tomorrow and can see what happens when it's hot and on the centre stand.

For what it's worth, the beast is on the side stand very rarely. It's stored between rides and throughout the winter on the centre stand.

 

[Slydynbye]

The Delkevic muffler and down pipe should fit in the Stock collector, swap the left one and see what happens.

 

[GGely]

Thanks, Slydynbye. I need to order a gasket set, as well as a set of fasteners, I bet. Hopefully have them sometime next week.

I’m inclined to try small things now and big things in a few weeks when the season ends for me. Once the Ninja 250 I’m working on is off the lift, it’ll be a lot easer to sort this one out.

 

[bdalameda]

Check your cab sync.

 

[Upt' North]

The drain holes puffing is completely normal on the standard pipes. If the bike was on the sidestand and the pipes are still standard and run through the collector then could it be that the exhaust gas and condensation was simply rising in the collector and up through the right pipe.
Like you say, check it on the centre stand, there shouldn't be enough water in there to block the left hand side but the inside of the silencer could well be imploding with corrosion.
I think I'd ride it, but, that's what I nearly always think.
Good luck.
Upt'North.

 

[Gerhard]

I had a mouse fill the exhaust with leaves and pink insulation one winter, maybe you know someone that has an endoscope to take a look inside. I bought one at Canadian Tire a few years back, it isn’t the best resolution but it does allow you to see where you normally couldn’t.

 

[GGely]

Carb sync was done about a month ago, so I’m sure it’s good. However, I lent the Carbtune to a fellow to do his CB900F Super Sport, CBR600RR Repsol and his CBF1000... poor bugger... So I’ll double check that in a few weeks.

You’re a man after my own heart, Upt’.

Good idea, Gerhard, I hadn’t thought of that. Coincidently, Garage Mahal happens to have such a camera in the inventory of tools! I’ll give that a good this evening, with any luck.

Thanks everyone!

 

[CYYJ]

Hi Gabriel:

It's normal for little puffs of exhaust to come out of the drain holes. It's not normal for exhaust output from the end of the exhaust pipes to be unequal.

I'm not sure how you could clean out any debris that might exist in a muffler - the only way I can think of would be to remove the muffler from the motorcycle and then force a lot of water through it, perhaps using a garden hose stuffed into the output end of the muffler.

Michael

 

[Upt' North]

Hi Gabriel:

It's normal for little puffs of exhaust to come out of the drain holes. It's not normal for exhaust output from the end of the exhaust pipes to be unequal.

I'm not sure how you could clean out any debris that might exist in a muffler - the only way I can think of would be to remove the muffler from the motorcycle and then force a lot of water through it, perhaps using a garden hose stuffed into the output end of the muffler.

Michael

Michael, I wouldn't be too happy with flooding the exhost just in case it's full of wadding. I think 10 miles at 6000 rpm would do the trick.
Upt'North.

 

[Andrew Shadow]

If it is the original Honda muffler they do not have any wadding in them- at least the 2000 model year didn't.

 

[GGely]

I’m not sure about the water trick but I’m not sure how the mufflers are built either.

For some reason, I don’t seem to have any issues spending time on the bike at all sorts of rpms, Upt’. Not sure why...

 

[Andrew Shadow]

The muffler that I cut open was off of a 2000 ST1100. It was similar in design to the below picture but smaller in scale. It was all steel piping and had no packing of any kind. I seem to remember that the pipes had a loop in them so a complete inspection via an inspection camera may not be possible.

From what I remember I don't recall any reason why running water through it would cause any harm but I would take it for a good long run afterwards however to make sure that it was as dried out as it can get. If you are going to do that you will have removed the muffler. In that case I would start with compressed air and see if the flow-through seems to match what you are putting in to it.

 

[Jim Van]

It would be interesting if the out flow wasn't the same as the input flow. Where would the difference in air be going ?

 

[Upt' North]

It would be interesting if the out flow wasn't the same as the input flow. Where would the difference in air be going ?

That old one Jim, witchcraft , although only usually descends around me when someone mentions volts.
Upt'North.

 

[Walleye]

Sure would be nice if you would speed up the diagnostics here GGely, I cant stand suspense, what 5 minutes to pop that sucker off. Maybe prior owner gutted the baffles in the right side and it is just following the path of least resistance, is it loud. Or maybe someone had it off and stuffed a rag in it to keep stuff out and forgot to remove it on reassembly, or, or.......

 

[Walleye]

Or maybe El Chiapo's boys filled it with rolls of hundred dollar bills.

 

[GGely]

Hey, Walleye, my apologies for slowing down the process. I’ll do my best to maintain the correct pace...



I want to have the gaskets on hand so that when I do pull the muffler, I can put a fresh one in there. I’m getting an order together and will probably get it sometime next week. To be honest, since the season will be over soon, I’d rather ride and save the diagnostics for a later date.

What I am going to do is send my camera in there to see what can be seen.

 

[Walleye]

Please, no apology required, I'm just funnin around but really am curious. I have a Two Brothers system on mine and can push a broomhandle all the way through. Is the Leo Vince a dual or single exhaust, never could figure why they put duals on most bikes, its unnecessary, Hayabusas and Ninjas dont need them, why an ST. Hope you can get caught up with things, and be sure and let us know what the mystery was.