hungrycamel

White smoke during warm up?

9 posts in this topic

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.

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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.

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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

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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

 

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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.

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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.

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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.

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