I posted this in the CBR F4 forum as well but thought it might help to post here as well.

Hey wondering if you guys might be able to help me out. I dropped my bike today going very slowly (it was dumb) Unfortunately it broke my mirror and snapped my shift peg Anyways, now when I try to start it when it's cooled down a little it won't start. The only way to get it going is to open the throtle with the choke all the way off and eventually after 2-3 times trying it starts and runs fine. If I try to use the choke at all I have no luck. If I just turn it off for 3-5 minutes after a good ride it starts right up no issues. Does anyone have any ideas? Bike is a '00 F4 (carbureated)

Thanks in advance...

 

That is odd. Usually when something like that happens you would not be able to start it with out the choke.

I doubt you have a lean/bank sensor (whatever it is called) which on a newer bike could be messed up.

Sorry no help

 

Not sure either. Check for minute cracks in case/covers, thinking maybe its drawing air somewhere which would require choke on, which doesnt really follow suit here. maybe knocked something loose in the carbs, but that doesnt really explain the warm starts. Usually its a tolerance thing when engines will only start when warm,( metal expanding). May want to run down the list, check spark on all cylinders, make sure all carbs are free flowing(open-close), check compression on all cylinders, etc. Process of elimination, hopefully someone has a better idea. Good luck.