Smoke on start up

[kitcrazy]

Started my bike this morning and got a pop and then a big plume of smoke  :eekI thought at first it was electrical but bike rode fine so would it be Un burnt fuel? And any advice how I fix it?

[kitcrazy]

Sorry should have said smoking came from the carb area

[Fazerider]

A sticking inlet valve I'd guess. If still open when the spark arrives it'll blow back igniting all the mixture in the inlet tract and blow out through the airbox. It probably sorted itself out after a couple of knocks from the camshaft, in which case there's no need to worry unless it makes a habit of it.

[esetest]

I have had the same sympton on mine a couple of times over the last couple of years , when its not been ridden for a few weeks, i initially thought it was electrical , but i have a feeling it was coming from the air filter housing . but as the bike is still going , i guess its nothing to worry about  .

[AyJay]

I had that after refitting the carbs once. I was inside the garage and absolutely shat myself with the noise. I had to go and wipe...


Just a backfire, I think. Bike's done 80k miles since then.

[unfazed]

Check the plug caps are tight on the Leads. Startup misfire is common enough if they are loose.
If they are are loose unscrew each of the 4 plug caps in turn and cut 10mm of the end of the lead and screw the cap back on.
That usually resolves it.