Hi! I have just got my learners and bought a GPZ250 of a guy and it was running fine..... when hot. But when it is cold, it just wont fire up. Choke on, choke off. Full throttle, no throttle. Push start, or jump start, still won't go. I can squirt some fuel into the cylinders and it will fire and run, but if you blip the throttle it will sometimes just stop. You have to carefully rev it up to keep it running then it is fine, untill the next morning..... Things i know Carbies clean. Diaphrams not split. Good spark. Compression OK. Tappets not tight. Runs good when going. Seems to tick over fast enough on the startermotor. Can anybody help with some ideas! Thank you.