intermittent spark at 1 and 3 cyl.

wot only gets to 4400 rpms and so cleaned fuel system...ie tank, hoses, filter and carbs. no change. then it would drop to 2300 rpm out of the blue at WOT and come back intermittently. and also run rough at idle. would reach 5000 in neutral WOT. Tach started going in and out. checked spark and had no spark on 1 and 3 and weak spark on 2. no. 4 stayed strong through all. moved coils around and problem did not follow. Regulator was putting out 12.6 v at idle and went up to 16 v as throttle increased. Changed reg, and CDI with one off a spare motor same problem but now won't start at all. could it be puls coils or charge coils?

There are a few things to check here. The service manual will give you all the specifications you are looking for, readmanuals.com is a good source of these. Take a look at the gap between the timing lobes and the pulser coil. Also check the output voltage of the pulser coil once you have adjusted the gap. Use a DVA adapter with your multimeter to check the voltage from the CDI to the ignition coils. Check the resistance of the high tension leads connecting the coils to the plugs, and finally check/ change the plugs. This should give you a complete end-to-end test of the ignition system to see where it is going wrong.

Stuart