85 venture has no spark on front cylinders at idle. rev to 2000rpm and spark is good.also tach drops to 0 when it happens. new plugs, plug caps,wires. checked tci for moisture. bike has been sitting for three years.any help would be appreciated.

85 venture has no spark on front cylinders at idle. rev to 2000rpm and spark is good.also tach drops to 0 when it happens. new plugs, plug caps,wires. checked tci for moisture. bike has been sitting for three years.any help would be appreciated.

Looks like a problem with the tci unit not sending pulses to the ignition coil feeding the front two cylinders as these

are also used to send info to the tacho. If it were mine I would take the tci unit off and leave it in the airing cupboard

for a few days and try again. I assume the battery is ok otherwise you wouldn't be able to start it.