White smoke? Advice?

[baz666]

83 GS750ES with 36,000 miles (60,000 kms) on the clock.
I'm getting some white smoke on start up lately.
I'm thinking maybe due to putting petcock on reserve a few times lately. Perhaps that caused a gasket problem or such, allowing a bit of gas to leak past into the cylinders and carbs.
Also, it's been cold out.
And there's no center stand on the bike due to a PO putting on a 4-into-1 exhaust so maybe gas is collecting in #1 cyl. The bike runs nice and clean and powerful once its warmed up so I'm not sure what's up.
Maybe a petcock rebuild should be added to my list of winter projects on the bike. I gotta ride this bike. I love it, sweetest bike I've ever owned and vastly underrated, imho.
Any advice at all would be appreciated.
thanks,
baz

[chuck hahn]

May be the valve guides ( or other seals ) getting a bit worn..the cold weather will tend to shrink them even a bit more while sitting. Once the bike warms up i bet it stops though. My 77 750 does the same thing from time to time, but it only uses about 2/3 of a quart of oil between changes so to me it isnt of great concern..yet. Please expound on how the smoke is after the bike has warmed up. The more details the better the analasis.

[mlinder]

Highway Glider is probably correct in this case. White smoke is water vapor. Water condenses inside the head in cold, wet weather after running. A few minutes of running, and it's gone.

[chuck hahn]

theres a BIG difference between the density and color of water vapor and oil smoke..he said it was smoke. Maybe he needs to clarify that point a bit clearer..after all i am sure he has seen condensation like from a car exhaust and can tell the differences..thats why i had posted that more details will bring a better analysis.

[mlinder]

People tend to call anything coming out of their exhaust 'smoke'.
White is not oil. Since these are not water cooled, there's no chance of a coolant leak.

Disappears after warmup, and white, almost assuredly condensation.

I've been wrong before, though.

[chuck hahn]

White is not oil?? Heres the facts..OIL burns WHITE. Too rich a mixture..meaning GAS..burns BLACKISH..Water vapor is more of a translucent white and much lighter than white produced by oil smoke.

[tkent02]

How long does this smoke last? Smoke from tired valve seals will be gone in a second or two after start up. What does this smoke smell like? Water, gasoline, oil or electrical smoke, those are the only choices. Another question, how far does it usually get ridden? The condensation will build up inside the engine if it never gets hot enough to boil it all out. More water looks more like smoke. Valve seals, condensation, whatever it is, ride the snot out of it and it will be fine.

[chuck hahn]

I agree Tom..ride it till its good and hot then ride it further to "dry out " the crankcase and then see what happens. Condensation will also collect in the lowest point in the exhaust. Some pipes have a small weep hole at the bottoms. Maybe take a wire and be sure they are open as well.

[mlinder]

White is not oil?? Heres the facts..OIL burns WHITE. Too rich a mixture..meaning GAS..burns BLACKISH..Water vapor is more of a translucent white and much lighter than white produced by oil smoke.

Oil burns blue-white :P It also smells different on the hand.

I personally can tell the difference between oil burning and water vapor burning. Some people can't.

It's true that it could be oil and he's dealing with worn valve seals, which is why it burns off after a bit of running...

Here in the cold and wet PNW, you'd be surprised how thick the condensation burn off can be. Collects in head, and pipes. Nice thick steam.

[chuck hahn]

I know how thick the water can be as i am in the frozen northern Michigan, but still its a totally differring look and smell that oil.

[mlinder]

I agree it's different. As I said, though, many people cannot tell the difference.

It's even more difficult for me, being somewhat color blind.

[baz666]

Wow, thanks for all the replies, folks.
The exhaust is white and doesn't smell like anything, not oil or gas or electrical.
It's fairly thick on starting up with the choke, gets thinner and after 1 or 2 minutes, it's gone and never re-appears while riding. There is no change in power delivery or the 1,200 rpm idle I'd set it at. The plugs are a clean tan color, no carbon, no white spots.
I guess I'm just paranoid cuz I love riding this bike so much, I worry about anything happening to it. I plan some remedial preventative or whatever you call that type of maintenance that keeps ya riding the same great old bike for a long time...
thanks to all for their advice. Amazing forum.
baz

[chuck hahn]

I went and started both my 77 and my 78 750 the other day and ran some stabil thru them for winter storage and guess what!! YUP!! Just like i was telling you earlier..lots of white smoke , then thinning out after a few minutes the completely gone when hot. That is because the valve guides are a bit worn but thats not an issue for me at this state. The bike uses a bit over 2/3 quart of oil between changes. You just got a valve guide thats a bit worn..no biggy. Ride it and just know its gonna smoke a bit till its warmed up..Now once it gets real bad then youll ahve to do a head job on it. But as its described right now its not an issue.

[baz666]

Well, the weather warmed up yesterday, nice and sunny out and when I started my 83 GS750ES there was no white smoke at all. So I'm guessing the cool, damp weather over the past 2 weeks was leaving condensation inside the exhaust and perhaps the cyl. head(?) as was mentioned. I filled up with 94 octane Sunoco ($5.14 a gallon in Canada!), ran it on the highway up to about 150 kph (90 mph). Afterwards, she ran nice and smooth, clean off-idle jump. And yes, that little tap tap tap sound of the valves at idle and just off-idle then snarling up the tach with that gorgeous 4-into-1 howl while getting wound out. Geez, I could wax poetic all day about this great little bike...
thanks for all the advice and reassurance.
baz

[Nessism]

If you want to treat your bike to something special please consider switching to something like Rotella Synthetic oil or a valve adjustment. Running expensive gas does nothing other than waste money GS bikes are designed to run on regular.