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


Herausgeber:  ERSATZTEIL- DIENST   Hans-Peter HOMMES       D-41748   VIERSEN   Tiefenstraße 10       Tel. 02162 - 8100933

Monthly available on our website.  


Inner- outer connections



© 2006 h-p hommes


BMW R75 and Zündapp KS 750 have the same connections (Antriebsglocke 3041) at the rear wheel drive.

Zündapp KS 750 has the same inner connection as BMW R75 at the transmission output and the outer connection is only similar. There the internal gear is smaller than the one at the rear wheel drive.

The worn out of the gears takes always place between the inner and outer connection. The fine geared shaft and the internal gear of the inner connection hardly have a strong worn out although they get hardly any lubrication.
The inner and outer connections must always be well lubricated. Otherwise they are quickly worn out. But who lubricates regularly?  

On this photo you can see two inner and outer connections of a Zündapp KS 750. Both are from the same drive shaft between rear wheel drive and transmission. The mileage of both is 12.000 km and both were new.

The right connection was not properly maintained that means not lubricated.
This connection is already totally worn out so that no power could be transmitted any more.

The left connection is still as good as new, because it was well lubricated and sealed with the propper rubber seal.
The old mechanic saying:   "Who lubricates well drives well"  applies here.

The connections are to lubricate every 5 - 7.000 km. for this purpose the locking ring and the rubber seal ring must be pulled out and new grease must be filled in. A solid, highly adhesive grease with  Molykote addiditive stands the test.

We produce a new drive shaft for the Zündapp KS 750, which can be taken out without disassembling the transmission and the rear wheel drive.
With this one it is easy to remove the connections or to to tighten the nuts of connection mounting.

                                                                                                                                                                   Order No 1035-1

Normally a self-loosening of the screws is not the case when you have new parts. But when you have mounted worn out connections and old bevel pinions a self-loosening of the screws can be foreseen.
When the screws of the bevel pinion loose themselves then the bevel pinion slips out of the crown wheel and works only partly.
A strong abrupt impact and the first tooth parts are cut off. This is the beginning of the self-destruction of the crown wheel bevel pinion set.
To tighten the nut of the screw connection is only a solution of short duration.
The operating forces are so strong that the nut will always loosen itsself when the gearing is not tightened enough.

Move the connections of your rear wheel drive a bit! Too much play?
Is it possible to move the connections axially?   

........the gears of the crown wheel and bevel pinion are already in the process of scrapping.
New parts wait for their first use. Your supplier is happy.

Now you ask yourself what you have done wrong again this time.  

Well good luck.


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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