Ok guys, I have an 06 YZ450 that is freaking impossible to start. To get it started I have to hold the throttle open slightly and kick for ever, it will also back fire several times when I kick it. I cant believe how hard this thing is to start. heres the mods, ported head, wb carbon pro, tokyo mods box(set on 2). I have checked engine timing its correct, I checked all the jetting but im not very good with jetting. NFPR needle 5th clip(counting down from top of needle) 172 main 45 pilot air screw 2 turns. I am looking for help im tired of kicking. also once its hot you might as well push it off the track its not going to start again. all help is greatly appreciated.