I have a 1999 Yamaha Yz400F. It is very bad with cold starting now and seems like it never used to be like this. I just recently changed the fuel like and carburetor line as well. It has a full White Brothers exhaust as well. It starts fine right after it warms up, but like I said it seems like it takes for ever to start. I would say at least 10 kicks. Also, how long should it typically take before I can run it and it is warmed up? Because I notice after a minute or two of warming up it will die. But after 5 minutes I can give it throttle and it is fine. It also pops a ton when I rev it up and let of the throttle. Any suggestions or help? Thank you very much ahead of time.