Excessive condensation from muffler

Not Dead Yet · Post by **Not Dead Yet** » Sat Nov 18, 2006 12:05 am

I bought my '04 (10,000 miles) with a Y/pipe-Remus Revolution-No Chip - removed cat conversion. I have noticed it emits what appears to be an excessive amount of condensation/moisture when I start the bike. Water sprays/squirts from the muffler end and drips from the Y-pipe/muffler connection. The bike is stored in a garage ranging from 50 to 70 degrees. I open the garage door and start it up without giving the bike time to acclimate to the colder outside temps. I have several other bikes and have never seen this amount of condensation emmision. Any thoughts, or is this natural for this bike.

Panzerleder · Post by **Panzerleder** » Sat Nov 18, 2006 12:38 am

That's quite a stable you have there NotDeadYet. How do you like the new Vespa? I'd love to have one.

As for your question, I think all exhausts emit a fair amount of water vapor on start-up, depending upon weather conditions. I have a Supertrapp muffler on mine, but have kept the cat (so far). Haven't noticed any abnormal amount of moisture coming out of it so far ... and certainly you shouldn't see any where the Y-pipe joins the muffler. You must have a leak there.

Not Dead Yet · Post by **Not Dead Yet** » Sat Nov 18, 2006 1:10 am

The Vespa is the only bike I've ever purchased new. Expect it to be a lifetime keeper. 65 MPG and 75 MPH on very stable 12" wheels. Lots of leg room even with my 6'2'/210 lb. frame. During the summer months(hot days), it's practically the only bike I ride when travelling in town. Guess you could say I love it!! Thanks for the input.

Post by **boxermania** » Sat Nov 18, 2006 7:01 pm

Not Dead Yet......it's hard to visualize your description of water spewing out, considering that the bike is air cooled.

The only logical explanation would be that you live in a very high humidity climate and after a ride as the muffler cools down that water in the atmosphere condenses inside the system and accumulates in the lowest point. Of course upon start-up isome is blown out of the muffler and some is converted to water vapor........

m@rco · Post by **m@rco** » Sun Nov 19, 2006 12:26 pm

I don't think it is very strange Not Dead Yet... The water basically comes from the fuel. Burning hydro carbons (CnHm + O2) leaves CO2 + H2O. When the engine is cold, the hot gasses from combustion condensate (phase change from gaseous to liquid) inside the relative cold exhaust. The flow of gasses "push" this water out. Whenever the engine reaches normal operating temperatures the exhaust becomes hot and the water will no longer condensate against a hot surface and will remain in gaseous phase. This is invisible.

Same thing you see with cars sometimes. Water running from exhaust when the engine is still cold.

If you have a continuous white cloud exiting from your exhaust, you may have a leak in the packing. A broken seal allows cooling water to enter into the cylinders. This excessive water does not evapote (saturated steam) and condensates into small water droplets (a cloud). This is not possible with your BMW bike since you don't have water cooling, but air to oil.

Does this help?

GeoffJ · Post by **GeoffJ** » Sun Nov 19, 2006 2:22 pm

All engines emit condensation. On cold days condensation coming from an engine looks like white smoke. Most likely, the aftermarket pipe has no weep holes like factory pipes. Weep holes are tiny holes in the bottom of mufflers that allow condensation to escape. If water remains inside a pipe rust will develop.

Not Dead Yet · Post by **Not Dead Yet** » Sun Nov 19, 2006 10:59 pm

There ya go....although I was pretty familiar with the whole condensation thing....I was more concerned as to why this bike seems to put out so much more than any other bike I have owned. I think GeoffJ may have hit it on the head for me given the aftermarket exhaust configuration I described above. This is the first aftermarket exhaust I've had on any bike. As always, thanks for the input gentlemen.

MIXR · Post by **MIXR** » Sun Nov 19, 2006 11:16 pm

Also - The free-flowing nature of your system actaully slows down the heating of the headers and can.

On a stock system, the back-pressure allows the headers to get hot really quickly, and the heated air vaporises the moisture coming in or already present to the point where it tends to be unoticeable in the exhaust gasses.

That's one of the reasons a 'hot' engine will not 'steam' for anywhere near as long as a cold one - the innards of the engine and exhaust system have already pre-heated any excess water vapour.

Either way, the biggest contributor to 'steaming' is either trapped water (from rain or washing) or a serious differential in outside temp to combustion temps, causing the air to 'condense' in the pipes.

Have a look on the net for info on jet aircraft vapour trails - all explained there.

Post by **boxermania** » Mon Nov 20, 2006 7:51 am

Not Dead Yet.....if you are that concerned, go to the lowest part of your system and drill a 1/16" hole. If water does accumulate the hole will allow it to drain out.....