I have had a similar problem with a 103 A2.

Eventually traced to something shorting to earth, within the Dip Switch.

Due to the very close proximity of the metal cover over the actual switch/wires, something was occasionally touching & shorting back through, down to the handle bars.

I fixed it by ...

11.1890 Listed as "insert for Lima Pullers"

See Kabine Tools section.

Is this a thread protector for the earlier type 175cc Kabine Crankshaft?

Prevents damage to the threads, when you are removing the Dynastart Armature?

Was only fitted & used on the very last Trojan's, I believe...

Can't see that making any difference whatsoever?

After all, it is the Crankshaft & it's Gear that are "driving" the Clutch (via the Chain) & not the other way around.

In operation, surely the top of the Chain is tight & the lower part slack, or am I missing the point of something here?

Regards,

Thanks very much for your helpful reply.

Luckily, I managed to find & purchase a NOS Lamp about a month ago.

Unfortunately, I had to pay a handsome price for it too!

If only I had known what Hella were planning & waited a while, I would have saved myself a lot of money!

Such is life...

Regards ...

Thanks for your help, will PM you soon...

Greetings to all, this my first post, concerns my search for some information concerning a missing part.

I have recently managed to acquire a very early Heinkel Kabine 150 BO, manufactured in 1956, which has a very low serial number, one of the first two thousand Cars made.
Totally original. never ...