400ex rebuild

[400exrideorrace]

Question riders I rebuilt a 400ex put a timing key in it and bored it over
20 when I go to start it runs a little but dont back fire acts like it
wants to run but will not stay double checked the timing seems to be on checked it a million times but is there a trick to it maybe or something I need to know bout it line the T face the cam lobes dont and spocket marks up is that all there is too it or am I missing something let me know wat u think guys

it is probably your carb, did you change the jetting or play withe the fule screw yet

[400exrideorrace]

The thing is I didnt mess with the carb and it ran before I tore it apart but smoked thats why I was thinkin it was timing