Hey guys, lately we have had alot of trouble starting my dads bike. For one, the bike will not start with the choke in, and will barely start without it. The only real way that we can get the bike to start is to open the throttle all the way and kick 5-6 times before it will finnally fire up. What is causing this? Is it a jetting issue? Or possibly a valve issue? Where would you guys start? The 450 is new to me, but this is what my guesses would be for why it isnt starting based on my knowledge from 250f's. Thanks alot. PS, alot of the time it will backfire more than once while trying to start it.