Hey everyone, i have a 2006 yamaha yz250f that i recently bought from a friend. It has been bored out to a 266 and has hotcams, drd exhuast system and some other stuff. Well when i first bought it, it was pretty easy to crank cold and hot but gradually it has been getting harder to start. Now, it WILL NOT crank cold by kicking it with choke on or off and hot start. I have to push start it to get it cranked but once its hot or even warm it will crank on the first kick almost every time, no matter how long iv been riding it. I service it routinely and i just put a fresh spark plug in it. It feels like it has good compression and the spark is good. It was just bored out and valves checked and everything by a trusted mechanic not too long ago when the previous owner had it. I have also messed around with the fuel air mixture screw hoping that was it but no success. It runs great when finally cranked but it is just a pain in the butt to get started. Any help would be greatly appreciated thanks!!