(Editor's note:  Peter Weidenhammer sent me this English translation of his
add-on transistor-ignition solution.  The link to his web page is at the
bottom of this explanation)



Here is an explanation of the transistor-ignition for the TX750: I designed it
as a pure add on-solution, which means, you dont have to cut any original
wires or modify any part. The benefits are: You don't need the condensers any
more, you just disconnect them and have an improved ignition during idle or
cold start. You rarely have to maintain the contact breakers, since their
wear is greatly reduced.

You need these parts for one cylinder: 2 Transistors (1x TIP 162 or TIP 161 or
similiar, 1x BC 557 or similar) 2 resistors (1x ~150 Ohms, 1x ~22k Ohms) , 1
Universal Diode (1 N4001 o.s.) and Zener-Diodes of total ~ 300 Volts (I took
2xZPY 160).

The function is simple: The TIP 162 takes over the hard job of the contact
breaker. The contact breaker ("Unterbrecher") makes the BC 557 leading via the
22 k Resistor, what means, that the BC 557 makes the TIP 162 via the 150
Resistor leading. The Z-Diodes protect the TIP 162 against too high voltage,
what may happen, when the coil ("Zündspule") is disconnected for ignition. The
red dot means, that you can connect 2 (or more) ignitions at that point and
you only need the Z-Diods once. The TIP 162 has a metal back which is
connected to the coil input. That means, that you have to isolate it with
special plastics insulators (available in electronic stores).

All parts together (for 1 cylinder) cost less than 5 Dollars and are available
in any electronic shop. I did the whole ignition (for 2 cylinders) in a ~10 cm
long aluminum U-profile which is stored under the seat.

You can integrate the ignition under the left side cover between the contacts
of the terminal coupler near the battery, where the wiring of the contact
breakers is connected to the wiring to the coils and condensers. You can pick
up the positive input for the BC 557 on the wiring to the coils. Thats all!
The ignition has worked very well in my TX750 since last year.

Peter's Web Page Link