my bike started acting up today. when i go to start it up i press the button and can hear it turning over but it won't fire up. with the choke fully on it starts up but really slowly and it stumbles till i give it a couple blips of the throttle. it eventually started to idle properly and i took it for a ride and it was fine. then i came home turned it off, let it sit for a few minutes and then tried to start it up again and the same thing happened. any ideas?? it's a 91 CBR 600 F2, 34k kms. i've had it for a couple months and haven't done anything to it so far. any help/insight would be greatly appreciated.