White smoke at start?

[bikerphil]

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

+1, my Kerker sometimes does that after riding in heavy rain.

[ManagerMike]

I'm kinda with Steve on this one, valve seals tend to wear collectively and would create a bluish-white smoke after a cold soak from both pipes, and not just one side. A gas flooded cylinder (or pair) would give whitish-white smoke from one cylinder emitted from one side.
If it were indeed A valve seal fouling ONE cylinder, most likely some other symptom would be present related to the failing valve or valve guide.
I'm thinking a leaking fuelcock on the left side flooding #1 and#2 cylinders.
Easy test; remove the fuel hose from the left fuelcock and see if it drips or not.
Even the best float valve in the world may pass some fuel from a gravity fed tank with as much as 5 gallons in it. If not, then why have any form of shutoff at the tank at all, vaccuum or manual, as all gravity fed tanks have? Main and reserve would suffice.