White smoke during warm up?

My '01 DR650SE has recently been blowing white smoke out the exhaust (FMF Powercore 4 btw, if relevant). It only does this for the first minute or two of warm-up, and I noticed it first when the recent cold, early-fall mornings started and the bike has dew covering the seat (I have to keep it on the driveway sometimes.)

Blipping the throttle shoots out a big puff of the stuff, but as I said, only for the first minute or two. Once idling normally, it's absent.

From what I've read, it could just be condensation, but I'd like some further confirmation to put my mind at ease. Some people were saying things about leaky valve seals letting oil in the cylinder while resting...

So, does this sound like harmless condensation? The smoke dissipates fairly quickly as well, but hangs around long enough to be noticeable.

is it consuming oil that you can detect?

how many miles on the motor?

check you airbox for oil.

Water vapor is the first option.  Stick your face in the exhaust and take a whiff.  Or have your little brother do it... Seriously though, that's the easiest way.

What should the exhaust smell like...?

I haven't noticed any oil consumption, but I may have slightly overfilled it on the last change; could that have something to do with it?

The odometer broke when I hit a tree a while ago, and it read 11,000; my GPS speedometer app that I tried to use on every ride shows ~3,000, so I'd say the bike is approaching around 15-17K miles.

And plugeye, why check for oil in the box? Obviously there's a bit of air filter oil smudged on the bottom - is that what you meant?

Edited by hungrycamel

i meant excessive motor oil in the box. sometimes the engine breather doesn't separate the oil mist enough & you end up with more motor oil in the box, especially when running on highway with motor wound up


Haven't gotten around to checking the air box recently, but I'll try to take a look soon. Today was around 40F in the morning, and there was a lot more than usual on warm up. Large cloud of smoke accumulated in my driveway because there was little wind. Seems to be worse with lower temperatures.

On 9/9/2017 at 2:26 PM, plugeye said:

i meant excessive motor oil in the box. sometimes the engine breather doesn't separate the oil mist enough & you end up with more motor oil in the box, especially when running on highway with imotor wound up


Well, turns out I owe you one for that tip... Took out the air box today and sure enough, the connecting boot to the carb was coated liberally in engine oil, and the box itself had some nasty pooling in the bottom. The bottom edge of the filter was soaked with a mix of engine oil and air filter oil as well. In the process of cleaning them up now; then I'll drain some oil because I definitely overfilled it on the last change, and that's what I assume was causing excessive buildup through the breather.

Don't like to revive a thread, but I think it's worth it to anyone who might find it later. 

Although the above solution honestly seemed to work for a while, as it got colder, the smoke returned, became far heavier, and the duration increased. Leaving school meant I left a cloud of grayish smoke in the parking lot that hung around for a bit. Always cleared up in about a minute though. 

Anyway, I decided on valve stem seals after further research - bought the seals, head gasket, and spring compressor. I'll change them as soon as possible and try to update this for future readers.

Changing the seals didn't fix the problem unfortunately. Still working to solve it.

Mine intermittently  smokes  (heavily  )upon  startup as well . It otherwise  runs really  strong  with  over 60 000  kms on an untouched  engine . It runs so well that I don't  worry  about  it . Does  not seem to loose or burn oil.

I have read  that using  2 liters of oil instead  of the recommended  2.2 liters will help with excess oil blowing  into the airbox.

Keep us posted  with your  findings  

Are you using ethanol??  reason i ask, is because in cold temps, alcohol gets thick and separates out of solution and sinks.  Also, since alcohol absorbs moisture what you get is basically a higher concentration of alcohol with a lot of moisture, getting fed into the carb, which can cause white smoke.  mine does the same thing too, when it's cold...I don't really worry about it...

Where I live ,it's difficult  to  avoid  ethanol . I don't  use it by choice . 

You have certainly  made an interesting  point.But, my other bikes  do not smoke  upon  startup  like  my dr650 . Still uncertain  as to why  it does , but otherwise  runs strong . 

Burning oil will make the exhaust more blueish or grey than white. As long as it's not a thick white smoke you're fine, it's probably just that when your engine is cold your mixture is a little fuel rich and the white is caused by unburnt fuel. When you choke it you're literally cutting the air supply. Try pulling the choke out just a hair less. If the smoke is grey or blue, make sure you don't have engine oil in your air box.

Otherwise, If you aren't turning your bike upside down or riding on extremely aggressive terrain, there really is no reason for there to be engine oil in your air boot and is an early indicator for a more serious problem and may need a top end overhaul.

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