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!

I had the same situation with a wonky cable going to the main-fuse (the one under the sidepanel). The had worked itself completely loose, recrimped it and now it's working better than ever.

Hope this helps
Greg

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

Ali, that is great to hear!,

the problems with my rev-counter and only the rear cillinder iginition now do make sense.
I already swopped the TCI before without improvement (or they must be both broken) so this all narrows it down to the wires to the coil or the coil itself. I have a spare coil, will swap that as soon as im home and check the wires  :)

@nanno: the main fuse wire under my side pannel was indeed crappy and already caused problems before, so that is in proper condition now. Thanx for the tip though!

:)

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?

Maybe it has really nothing to do with it, but it is done very quikly and make things sure : take off the little vacuum hose  of the back cyl. petcock and put in a screw or something to close it, go on "Pri" and have a test,
just a guess, Regards Ali
P.S.: there can also be a problem with the connector -the one which goes to the TCI- located behind the airfilter  or the pickup  responsible for the backcylinder, it can cause "no spark",
even the TCI has no malfunktion, in that case the TCI gets no signal to give a spark, and of course- sometimes its the simple things- use a new sparkplug