cold-starting

Hi all, I will be working on the bike in winter, I have a new coil and plug leads, and I will pull the carbs. I took it out yesterday for a 50-mile ride and in the beginning after a difficult cold start the idle was 1000 to 1500 RPM but by the end of the ride it was racing at 3000 RPM, it's...

Is it age or something else that's causing the bike to require ~10 minutes idling with the starter jet lever (choke) ON before it's drivable with the choke OFF? When cold, the bike usually starts with one kick (or a coupla cycles of the decompression lever) with the starter jet lever (choke)...