Intermittent Exhaust Smoke On Start Up

[DarkSideR]

About every 50 starts the bike will belch white smoke for just a second. I haven't been able to see if the smoke comes from one or both exhaust pipes.

Any ideas on what could be causing this?

[BonS]

My friends Valk does this on the left side only. Either on start up or after deceleration. For him it's valve seals. Runs fine otherwise. We'll be working on it this winter after riding season.

[Patrick]

Its probably just condensation. These flat engines sometimes get a case of loose valve guides every once in awhile, but, that doesn't hurt anything.

[Michvalk]

Humidity, condensation, Hot to cold. White smoke for a minuet or two is no big deal.......Really

[DarkSideR]

Humidity, condensation, Hot to cold. White smoke for a minuet or two is no big deal.......Really

Not a big deal until someone asks to hear your bike and it poofs white smoke. 

[F6Dave]

Sometimes I think these engines can stop in just the right position where one of the cylinders has enough vacuum to suck some oil past the rings.  Then it burns off when you start it.  On both of mine it happens only on the left side, since the engine leans that way when parked.  My old BMW airhead does it to.

[Dorkman]

White smoke is water, blue is oil.  A puff of white smoke is likely just condensation.  If it gets worse, it could be a head gasket.

[DarkSideR]

Any possibility that the gas could occasionally run down the vacuum line from the petcock? This would explain why it puffs on one side. I think raw fuel in a cylinder would cause a puff of white. I do believe the vacuum line connects to the left side of the bike.

This makes me wonder if guys who have replaced the petcock with the piggle are experiencing this?  ???

[The emperor has no clothes]

Humidity, condensation, Hot to cold. White smoke for a minuet or two is no big deal.......Really

Not a big deal until someone asks to hear your bike and it poofs white smoke. 

Just tell them you are also a part time cropduster

[Michvalk]

Any possibility that the gas could occasionally run down the vacuum line from the petcock? This would explain why it puffs on one side. I think raw fuel in a cylinder would cause a puff of white. I do believe the vacuum line connects to the left side of the bike.

This makes me wonder if guys who have replaced the petcock with the piggle are experiencing this?  ???

Yes, there is a possibility of fuel running down the vacuum line. If this was happening, the smoke would not be white. A rich condition would produce black or very dark blue smoke

[custom1]

The chances of fuel running down the vacuum line are slim, VERY slim. For that to happen BOTH diaphragms inside the petcock have to be bad and someone would have had to block off the weep hole at the bottom of the petcock, because even if just the fuel side diaphragm is bad the fuel would run out the weep hole before getting to the vacuum line because the vacuum side diaphragm is between the weep hole and the vacuum line. Now after its running it might suck some fuel down the line (if both diaphragms are bad) but it would still be running from the weep hole first. So if the weep hole is dry there is no fuel in the vacuum line. Plus if the vacuum side diaphragm is bad the bike will not run very far, because it will run out of fuel.
Really what are the chances of both diaphragms going bad at once.

The white smoke has to be water, either condensation or coolant.

[Jess from VA]

After the bike sits a few days (leaning left on the kickstand), go out and start it off the bike and back up watch the little bit of white smoke out the left (low) exhaust....... they all do it.

Now if it's something worse, then worry.

[Moonshot_1]

I would think raw fuel in a cylinder would cause a case of hydrolock. Any smoke would be bluish as stated before.

I'd say it's a condensation issue. The bike leans to the left so the condensation would migrate that way.
Start it up and the condensation is turned to steam and "poof", a brief period of white smoke out one side.

You relate no other issues so we can make an assumption that there are none with the exception of the occasional white smoke out the tail.

I too get the occasional white poof of smoke on start up. Humid weather and weather changes (hot to cool) seem to precipitate it.

[Denny47]

White smoke is water, black smoke is fuel, blue smoke is oil.

[Bigun]

The old 1100 wings were famous for belching one color or the next if left on their side stand for any length of time.

[DarkSideR]

 So 5 Valkyries ride down to a local hang out. 5 Valkyries park right next to each other on the same slope. 5 Valkyries sit for the same amount of time. 5 Valkyries start at the same time, mine is the only one that belches.  Doesn't this rule out heat, humidity, and lean angle when parked?

[salty1]

So 5 Valkyries ride down to a local hang out. 5 Valkyries park right next to each other on the same slope. 5 Valkyries sit for the same amount of time. 5 Valkyries start at the same time, mine is the only one that belches.  Doesn't this rule out heat, humidity, and lean angle when parked?

Do you use Seafoam? If the mixture is to rich, it can result in belches of smoke. Most likely valve seals. FWIW

[Michvalk]

So 5 Valkyries ride down to a local hang out. 5 Valkyries park right next to each other on the same slope. 5 Valkyries sit for the same amount of time. 5 Valkyries start at the same time, mine is the only one that belches.  Doesn't this rule out heat, humidity, and lean angle when parked?

No, not really. Depends on the condition of your bike and the condition of the others. Too many variables to make an educated guess

Are you losing antifreeze from the overflow bottle and/or radiator? Does the  bike run hot? Have you noticed bad running? Checked the plugs for deposits that would indicate contaminates in the cylinder when the plug fires? I think you are unnecessarily worrying over nothing, but, these things are an indicator of problems. You could also do a compression check for a more difinative answer.  

[john]

          nature of the beast ...           
           no worries         

[Chillerman]

Josh, I have nothing to add to what others have said, but I will take that POS of your hands if you don't want it any more 

[DarkSideR]

Josh, I have nothing to add to what others have said, but I will take that POS of your hands if you don't want it any more 

It's only  POS .01% of the time.

I don't mean to be argumentative here, or imply I'm not happy with the mighty Valk. There was some great advice in a previous post in this thread. I am going to look into a couple of things.

[F6Dave]

Quote:  So 5 Valkyries ride down to a local hang out. 5 Valkyries park right next to each other on the same slope. 5 Valkyries sit for the same amount of time. 5 Valkyries start at the same time, mine is the only one that belches.  Doesn't this rule out heat, humidity, and lean angle when parked?

Startup smoke also can be related to the crank position when the engine completely stops.  Any of the 6 cylinders can end up in any one of the intake/compression/power/exhaust stroke positions, which can affect what kind of fluid gets sucked into the combustion chamber to make some smoke when the engine gets restarted.  Lots of things at play here.  But just check the net and you'll find countless posts about horizontally opposed MC engines (BMWs, Wings, and Valks) smoking on startup.  It's VERY common.  And if it only happens at startup I would not worry.