The BMW R12 used 4 different types of Spark plug caps during its production run leaving the factory. They are the :
- BERU 04
- BOSCH 0356 150 005
- Seimens EW(S)10b
- BMW marked cap
- BOSCH EM/W 10/11
Below are several photos of the BERU 04 spark plug cap.
Below is a photo of the BOSCH 0356 150 005 model spark plug caps.
Below are photos of the BOSCH EM/W 10/11. These type of plugs were the first Funkentstört nach Gruppe III sparkplug cap. This was to reinforce against radio interference.
Here is a spark plug conversion sheet: