If ALL plugs spark and 2 + 4 cylinders run ok it's NOT the timing or coils.
Timing and coils are paired to 1 -4 and 2-3 so if the timing is right for number 1 cyl it has to be right for number 4.
Forget timing and coils.
Cam timing will be ok too so start by looking at fueling especially the pilot circuit , if it's CV carbs look for split diaphragms and then compression but unless you have zero comp due to bent or non seating valves etc there should be some combustion enough to warm the headers.
Also check for split/leaking carb mounting rubbers on those cyls as the engine will draw air rather than fuel if that is the case.
Daren, I know you said that there's good spark, but I would go ahead & redo the spark plug wire connections at all points. The plug wires are removable from the coils by unscrewing the ribbed compression boots. If the wires have the white crusty oxidation, nip off the ends a tad but not too much. Even if it's not the problem, it's easy. It wouldn't hurt to go ahead & replace the plug wires... assuming they are the original 30-yr old stuff.
My bike was firing intermittently on #1 & #2 but doing the above solved the problem - I though there was good spark -- checked in a darkened garage at night.
check and double check your firing order, I'll admit I ran a bike once I swore the plug wires were right, I knew when I took off, down the road on 2 cylinders i had the wires wrong, double check!
I did triple check and they are all in the correct order. I will try suggestions from other people. Thanks guys for the help I will report back laterwhen I have time to work on the bike.
