No spark to plugs.

[rranger]

Electrical is sorted out, it appears a wire off the coil to the choke was the culprit, as soon as I removed it the electrical fell into place and I had good spark to the plugs. Will have to hook it up elsewhere. Tried firing up yesterday. Its backfiring into the intake manifold. So I tore it down to double check check the timing and it looks ok to me. The marked links on the chain are 20 links apart, and my cam mark and crank marks are still 20 links apart. So to a layman like me that appears to be correct. The crank and cam marks are basically at 3 o'clock when number 1 is at top dead center, and 20 links apart..
Even still I'm getting a pro to check the timing this morning. Assuming its ok, could a bad valve job and head rebuild cause the backfiring? Or is it possibly a Carb issue. Which is a Weber. When i started this project my plan was to rebuild the engine and get it running with the known to work Mikuni carb to simplify the issues. Then do the carb transfer to the weber after I had the motor running. But I jumped to the weber while rebuilding, and I'm wishing I stuck to plan A.