White smoke at start?

[tri650]

I think I know what this means, but if anyone has any other ideas let me know. White smoke at start for about 10 seconds out of the left exhaust. Plugs look a little black - maybe a trace of oil. Not the normal tan. I will be doing a compression check to see what it shows. Anything else I can be doing to determine cause of smoke? Thanks.

[natemoen]

Usually if it is only at start up and goes away after a few seconds then it means the valve seals are leaking.

[Redshirt]

Question on same topic: Could this be associated with flooded carbs on kickstand-leaning side?

[natemoen]

Question on same topic: Could this be associated with flooded carbs on kickstand-leaning side?

Most likely no because excess gas creates a black sooty smoke, oil makes the white/blue smoke.

[brcree]

smoke

I agree with Nate:

[tri650]

How do I determine if the valve seals are leaking? Could it also be rings?

[B.B.]

I had the same prob, so I took out all spark plugs, added a couple of drops of transmission fluid in each cylander, and waited a few minutes. Then hit the starter button a couple times to blow out any excess fluid before replacing my spark plugs. (Dont add much because it can sieze up the motor). It really white smoked upon start up and blew white smoke for awhile but eventualy stopped and I have not had that problem since. Not sure why or how this helped but it did. There are a lot smarter people with a lot more expirience on here than I have though, so you may want to ask around before doing this.

[natemoen]

How do I determine if the valve seals are leaking? Could it also be rings?

Most always if it is the rings that are the problem they will smoke constantly while the bike is running. When the valve seals leak they for the most part only are a problem once the bike is turned off and then the oil in the head runs down the valve stem and puddles in the cylinder or on top of the valve head, so right when you start it up that puddled oil will burn off and then be gone till next time she sits for a little bit.

Only way to really know is to pull the head and replace them and see if the smoke goes away....

[tri650]

That is more the situation - it blows smoke for about 10 seonds and then runs clear. Would a compression test give me more direction on the rings? Plugs - what should I be looking for?

[natemoen]

That is more the situation - it blows smoke for about 10 seonds and then runs clear. Would a compression test give me more direction on the rings? Plugs - what should I be looking for?

It could, but I doubt it. If it is the valve seals they have nothing to do with compression, just oil control. By the way you say it is behaving I doubt that it is the rings. Does the bike run good otherwise? How long have you had it?

[crazy steve]

White smoke at start can be excess fuel; if raw fuel is getting into the cylinder that's what you'll see. Valve seals/guides will also be white, but with a blueish tint, and you'll usually get much less volume of smoke. If you're laying down a good-sized cloud, look at the carbs.

[cywelchjr]

If it's the seals it CAN be because they dried out from sitting or it can be because they are damaged. If they are damaged there is nothing you can do short of replacement. If they are dried out, there are seal revitalizer products out there these days that WORK. The ones I have found that work are all thicker more viscous products, which when I looked up what they contain is basically the same stuff that motor oils contain to keep the seals from drying out in the first place (many people don't realize that the oil in the engine is in part designed to keep the seals from drying out and shrinking, and and engine sitting with no oil getting to the seals, that's one of the things that goes bad). I put the stuff in ANY engine that I put into service that's been sitting for more than about a year, and on engines that were exhibiting leaking seal problems, in most cases it has stopped the leakage (the cases where it didn't and I tore into the leaking area I found damaged seals, which these products cannot do anything for and don't claim to be able to) within a pretty short time.

With these engines I typically use about half a dose, based on crankcase capacity vs automotive capacity, and generally it's a one time treatment, if that doesn't do it, IMHO you need to go in and fix the problem anyways cause they are too dry for this to work. Also, I've never had it cause any problems with the clutch on any wet clutch system I've used these products on, they are NOT friction modifiers.

[tri650]

To answer a few questions:
Bike runs great. No problems starting or running. When it sat for a week or more I got a really big cloud of white smoke for about 5 seonds - then less smoke and then it was clean.
What would be wrong with the carbs for them to flood the cylinder - stuck float? What else would I be looking for in the carbs?

[crazy steve]

..When it sat for a week or more I got a really big cloud of white smoke for about 5 seonds - then less smoke and then it was clean.

Again, you need to look at the color. Plain white, it likely fuel and you may have slightly leaky float valve, petcock, etc. If it's got a blueish color to it, then it's probably valve guides/seals.

[foreda]

The white smoke is not smoke.. It's probably water vapor in the exhaust!