when cold bike rev's

[Rota Ash]

when the old girl hasn't been started for a while i have to use the choke to get it started, although when it fires it revs like crazy and i have to turn the choke off as soon as i can, even then it has a high idle untill it warms up.. ? normal? or is my jetting wrong

[Coop]

How long is "awhile"? Could be the carb is gummed up from sitting and the slide is sticking a bit.

[SachsGS]

Sounds like you have an airleak somewhere. Make sure your throttle cable isn't too tight, in other words that the slide is bottoming correctly. Look for a crack in your carb boot between the carb and cylinder and make sure that your float height isn't too low, you could be drawing air through the pilot circuit. Pull the mag cover off and look for "goo" running down behind the flywheel, an indication of a leaking crankseal. If this is an aircooled bike, look at the base gasket area to see if a leak is developing there.

[G-MONEY]

Air leak,take a can of brake cleaner spary it around all the spots SACHS suggested it will make the engine faulter and you can zero in on it.You might find you have more than one leak.

[Coop]

The only reason I didn't suggest air leak only because the OP suggested it only happens when the bike sits, not every time they starts the bike. But I agree, definitely symptoms of an air leak.

[125mx.com]

Could just be a lean pilot circuit, as it warms does it calm down !

[evo550]

Is it air or liquid cooled?
I have had these symptoms before in an old air cooled motor, it turned out to be a leaky base gasket.
When cold the cylinder and crank surfaces shrunk (as metal does when cold) allowing air to be drawn into cylinder upon start up, as the motor heated up the metal expanded, the gap between the two surfaces closed and air leak cured.