Often the ignition amplifier can go on the fritz. It is the black box held onto the body of the dizzy by 2 screws. Firing order 1342 anticlockwise. Make sure that when you looked at TDC that as well as the crank mark; the cam arrow was pointing in the right place else you could have been 180 degrees out.
I would re check that then look at a replacement dizzy and or coil and check the airflow flap is not sticking open forcing more fuel then needed. To dispel fuel in cylinders/manifold diconnect pump (or the pink relay under dash), open throttle to full and crank motor 30 seconds or so.

let us know how u get on m8