Motorcycle Repair: honda shadow vt500c ignition puzzle, pulse generators, honda shadow

Question
hi,
i have inherited a 84 honda shadow, not running(starts occaisionally) i determined via ohm meter that pulse generators were defective, replaced and check out ok. but get this, when i go to start the bike i heard a buzzing sound. determined this to be the spark plug firing constantly. almost like a Frankenstien movie. both plugs are arcing steady. what is going on. i'm guessing spark boxes. don't see any shorts in the harness. any suggestions. thanks in advance

Answer
Bruce,

are all spark units buzzing? Does it stop
when you disconnect the pulse connector?
Sounds like you might have to get a wiring
diagram to check things out. Have you
tried switching the spark units if possible.
Check all the connectors for loose wires
and corrosion. Try removing the battery
cable for a few minutes and reconnect it.
This might help to reset the electronics.
Make sure all your ground wires are tight
and clean. Is the battery fully charged?
Some systems won't operate properly
with a low battery.
Does it buzz with the old pulse generators
connected? Maybe a wiring fault on new one?
Make sure it is the spark units making the
noise.