Moin Leute!

Ich schreibe mein Problem auf English weil das fur mir (bin ein Hollander) einfacher ist. Reagieren koennen sie einfach auf deutsch, lesen geht mir leicht .

The problem with my bike is that when I accelerate harshly in a low gear, the engine holds back shortly(as far as I can tell it seems only to shut down one of the two cillinders) and then gives full power again. During this process the revcounter drops to zero (while the engine is still making revs). This seams like an electrical problem? but how can the revcounter fail together with only one of the two sparkplugs?

Also the rear sparkplug is charcoal black (not wet with oil).

I already exchanged the carburators and fueltaps without any improvement, so why is my rear sparkplug black?, does not seam to be a fuel issue. I have read that it can also be caused by a failing iginition system or weak spark. I have checked my sparkplug outside the engine and it gives a powerfull blue spark.

who can help me out? or give some hints?

Im voraus vielen Dank!

The Rev-Counter gets a signal only from the back-cylinder, if there is no ignition / nothing coming from the TCI / it will show zero. So i presume your problem may be caused by the TCI or  contact between TCI and coil,
regards Ali

here is an update,

I swopped the ignition coils without improvement: the rear sparkplug stays black and the revcounter still dies when the engine power decreases. The revcounter only dies sometimes when I accelerate fast in low gear. The sparkplug however gets black all the time (and real fast).

I already checked the pickup coils on resistance, disconnected the revcounter to make sure it doesnt shortcirquit the sparksystem of the rear cillinder, and connect test wired to make sure there arent any faulty wires.

This leaves the TCI, but I swopped that with one I had lying around: the problem stays exact the same. (however the TCI could have the exact same problem).

Anyone some experience?