Powerdynamo brings new ignition & light 
to your classic bike

 

   

stock 12V dynamos for BMW R50/2  - plenty of room for error in replacing with Powerdynamo

Note, room for error, there have been at least 3 different stock 12V systems for BMW flat twins (most of them in R50/2 sold originally to police)

1)

There have been BMW with magneto as in all 6V BMW, but 12V Dynamo with 4 carbon brushes and base diameter of  98mm



Known here are especially BMW R 50 /2
Crank pin was 20 mm version, Dynamo has label "BOSCH CH LJ / C  GE 100 / 12 1800 R 7". Diameter of base as in all 6V BMW dynamo 98mm. Pitch circle for fastening screws 85mm.
Replacement for those would be our system  System  70 81 999 020 

please know that in low revs our system may develop less lighting output than the stock 12V/100W system.
You find an output diagram here


2)

There have been BMW with magneto as in 6V systems, but 12V dynamo with base diameter of 112mm (we have no picture of the dynamo, but of the front cover of such arrangements)



Here also known BMW R 50 /2

The seat of the dynamo has actually 2 centering levels. An outer with 112mm, and further in one with 108mm, crank pin is 20 mm, dynamo is labeled: "BOSCH CH LJ / C  GE 100 / 12 1800 R 7". Pitch circle 85mm.
Replacement for those would be our system  System  70 81 999 020 but complemented by Adapter 70 81 999 09

3)

There have been BMW with 3-phase alternator (recognisable on 3 fastening points in contrast to 2 in dynamos)



Known here also BMW R 50 /2

Base diameter is 105mm, we however also had cases with 104mm.
Note: later 3-ühase alternator had 107mm.
Here we do not offer a replacement any more since our  System 70 64 999 00 was discontinued.