Little more info would help .
Are you ---
1) getting gas to the engine ?
2) getting spark all the way thru to the ends of the plugs ?
3) silly question I know , but ...... do you have compression ?
( knew someone once that did a top end rebuild and forgot
the piston ring
So , anyway .... it won't start ....
if you HAVE gas , and you HAVE spark , then , its a matter of something somewhere needs to be re-set . ( re calibrated , or .... )
So , tell us what is happening and whats not .