Rookie question backfiring won't start

[simplesence]

So I swapped out the engine earlier and replaced the advancer points plate. Coils r ok far as I can see. Wires 1-4 r on plugs 1-4 in the seemingly correct order. Is it a timing issue. How do I fix that?

 

[AlphaDogChoppers]

You probably have the two coil connections swapped, so your plugs are firing at top dead center between the intake and exhaust stroke instead of at TDC of the compression stroke.

 

[simplesence]

They seem right to me. Yellow to yellow and blue to blue.

 

[AlphaDogChoppers]

I just love it when you rookies decide that you have to argue with the experienced mechanics. :

 

[SimJen]

He didn't seem like he was arguing?
He was merely stating that he thinks they are correct!
Backfiring is usually due to mis-timing, whether via incorrect cam timing or ignition running out of sync as per Alphadog's comment.

 

[AlphaDogChoppers]

Something is 180 degrees out of phase. It could be the whole trigger plate, or just misconnected coils. Just because the colors match, doesn't mean it's right. A very quick test would be to swap the coil connections. Fast, easy.

 

[simplesence]

It was the points cam.

 

[SimJen]

sweet, that was easy then
Thanks for coming back and informing us of the solution.