[fizzwheel]

Carb heaters come on with the ignition, but IIRC the general opinion of those in the know, ( i.e not me ) is that they are next to useless anyway. I dont think your problem is that your carbs are to cold. I think your problem is more likely being caused by poor fueling / carb setup.

How does the choke lever feel to move ? Does it move freely or is it stiff / difficult to move.

Could be your choke plungers are stuck on the carb's as this is quite a common problem. Could also be something else not right with your carbs. So thats probably where I would start looking.

The other thing you could try is start the bike wait for it stall / die. Then pop the plug out and have a look at it, see what colour is it, is it wet, does the bike stink of petrol etc etc.