I know you have B-O plates, but do you have stick coils. New spark plugs does not mean good plug wires.
No stick coils. Is there a way of correcting the possible no spark problem without spending another boatload of money on stick coils for this bike?
If the coils are good, Murph's sells a rebuild kit.Thats one option. Unsrew the plug wire from the plug boot. Look and see if the inside of the wire is green or discolored., Trim about 1/4" off of the plug wires and screw them back into the boots and see if that makes it any better. The manual has a good check list for testing the coils. I just dont have mine with me.
http://www.murphskits.com/catalog/product_info.php?cPath=1_92&products_id=51
I was able to determine that it was a missing stopper on the middle carb. Prev. owner had taken a small piece of vacuum tube and inserted a self tapping sheet metal screw in the end and I guess my riding it had caused it to loosen. Put on a cap and it runs like a top again.