Technical Information Pages for the Restoration of the heavy military bikes BMW R75 and Zündapp KS 750.


Editor:  ERSATZTEIL    DIENST       Hans-Peter HOMMES       41363 Jüchen Kamphausen 156 C/2

Monthly available on our website.  


Temperature engine - magneto



© 2013 h-p hommes




At this year's Pyrenees trip in October, we have repeatedly made comparative measurements of the temperature at the engine, the engine oil and the magneto at our four Zündapp KS 750. The outside temperature was about 22 - 26 ° C.
Please note that we have made only comparative measurements at the same conditions.
After a road trip, after an off road trip or after a long steep ascents.
All bikes had the same exhaust system and the same carburetor and magneto assembly.
We measured with an electronic temperature sensor with laser pointe.r

The result was sometimes quite amazing.





Temperature differences between the left and right side of the cylinder almost always ranged between 10-15 ° C. Sometimes it was the right and sometimes the left side that showed higher temperature.

The engine, which is known to us as the fastest and best running one for years,
had compared to the other three KS 750 always 10-20° less temperature.



Temperature measured directly after stopping.

Measuring point between 1st + 2nd fin see photo A.

Road trip with 70-80 Km/h                              120 - 135°C

Off-road trip easy terrain                                  110 - 120°C

Difficult terrain, long steep mountain pass      180 - 210°C      


Noris Magneto:

The magneto showed - compared to the engine temperature -always a temperature which was approximately 50% of the engine measuring.

After the engine is switching off the magneto heats up another 20-30 °.

This explains the frequent starting problems with a hot engine.
However, we had no problems to start at these temperatures, because we all have good ignition coils in our magnetos.


Temperature measured directly after stopping .
Measuring point on right hand side see photo B.

Road trip with 70-80 Km/h                                60 - 70°C   after 5-10 min. 80°

Off-road trip easy terrain                                    60 - 65°C  after 5-10 min. 80°

Difficult terrain, long steep mountain pass         75 - 95°C  after5-10 min. 110° *

 * Engines started even then without any problems.
   We have tested our ignition coils and had the first misfire only at a temperature higher 140 ° C.

Old coils that we tested had the first misfire at 85 -95 ° C.
Conclusion: the old coils need to cool down to 40-50 ° C in order to work again.


Oil temperature: Measured by dipstick and gauge to oil pan  

Road trip with 70-80 Km/h                              110 - 120°C

Off road trip easy terrain                                      80 - 90°C

Difficult terrain, long steep mountain pass     120 - 130°C        never more than 130°






We offer:

Spare parts + Accessories + Repair for Engines, Transmissions, etc. of 
Zündapp KS 750 and 600

We offer:

Spare parts + Accessories + Repair
of BMW R75 and Zündapp

H-P Hommes Ersatzteil-Dienst
Ersatzteile + Instandsetzungen
repairing + restoring

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