Right hoping for some confirmation on a digiplex 2 ignition fault, my 1990 bike has stopped sparking on the rear cylinder at 3700 rpm rev it up and rear cylinder cuts out, remove plug cap ground a new plug confirm s spark literally stops!, changed coils wiring from front to back and surprisingly it still stops sparking on the rear cylinder which indicates to me pickup or digiplex, pick up either works or not as far as I know and front is fineso assuming a new digitplex is required, front cylinder is fine on either coil and everything else passes as ok any thing I have missed? And I also assume a Paso 750 digiplex would work ok, air tube is also ok as is the digiplex earth HELP :-)

Hi, did you changed the coils also from vertical to horizontal..? Suppose you allready tried other spark plug cables etc to be sure..?

check the ignition switch

Has the pickup-line the greatest possible distance to the ignition cables?

Yes 're coils, rewired them both, same fault, the pickup is working fine to the horizontal cylinder and both cylinders are fine to3700 rpm when the rear stops sparking, ignition switch must be ok because it's starting fine

But the ignition switch is well known weak point and can develop resistance across the contacts dropping the volts on load. If the volts are down that could be a reason for the sparks stopping on the rear cylinder. The rear may be more sensitive to a reduced voltage. The cure for the ignition switch is to fit a relay to do the switching, triggered by the ignition switch.

Paso ecu fitted and now perfect :-)

just got lucky, was a wiring issue most likely