smoking when choked on startup

[Guest]

Hello all,

1978 GS 1000 seems to have white smoke on startup when choke is on. Once warmed it and under normal riding conditions, this goes away? any idea what this could be? I know the choke creates a rich condition, but I would have though that smoke would have been darker? any thoughts are appreciated.

stock engine, full 4to1 exhaust with pods and fresh oil change. valves in spec, compression good.

Thoughts?

[Sandy]

Probably old crusty valve seals. They let some oil past when parked hot and burns it off on start up. You may notice increased oil consumption but if compression is good and it's running fine you might just ignore it until it becomes annoying enough to replace.them. Mine did that for quite some time before I decided it was too annoying and fixed it. If that's what it is there is a way to change them without removing the head but most here pull the head and cylinders and change the rings at the same time.

[greg78gs750]

get a buddy to follow you, puff of smoke on decel is another sign of valve stem seals. Though chances are after 30 + years they are due, no diagnosis necessary.....

[derwood]

steam? ...from water vapour condensing in the exhaust system

[Brendan W]

Exhaust gas dewpoint is about 70C/150F. Until the silencers have got to that temperature you can expect to see steam.
There is a lot of talk about the colour of oil/fuel/steam and I have concluded that I am colour blind
Valve seals failing does show for a bit after starting and smells of oil and sometimes there will be a difference between the left and right silencer, assuming you still have a 4 to 2 system. One valve is generally worse than the others and generally exhaust valves take a bigger beating.
As the guys said, after 30 or 40 years you can be sure that they are leaking to an extent.
There are ways to change the seals without taking the head off and if for some reason the exhaust headers happened to be off you can sometimes see a bad leaker dribbling down the stem of the valve.

[Wolfdogg40]

get a buddy to follow you, puff of smoke on decel is another sign of valve stem seals. Though chances are after 30 + years they are due, no diagnosis necessary.....

Doesn't really look like steam to me. seems to hang around a longer that I would think steam would?

[Brendan W]

Doesn't really look like steam to me. seems to hang around a longer that I would think steam would?

How long is longer?

[Wolfdogg40]

How long is longer?

it seem to rise and fall and hang around a little longer than I have seen steam do.

[derwood]

steam do fall and hang a little rise longer?