strange failure on R27

[wolfchen75]

Riding my R27 the red generator light suddenly came on, rode it home on battery, pulling off the generator cover I saw that both wires from brushes to connection had come loose at joint at the same time ? how is this even possible ? I mean the screws were tight and the wires broke off at the tabs ? one I could imagine but both at the same time ?

[schrader7032]

Would be interesting to see some pictures.

[wolfchen75]

well i already reattached loose wires but to my chagrin generator light still on

[schrader7032]

This manual might help...it's the early version about the electrical system. There is an updated system which specifically addresses the various models and also has color diagrams.

https://www.snafu.org/restore/uandm_bmw_v1.pdf

[scottiesharpe]

Did the solder melt on the wires due to a short circuit?

[wolfchen75]

This manual might help...it's the early version about the electrical system. There is an updated system which specifically addresses the various models and also has color diagrams.

https://www.snafu.org/restore/uandm_bmw_v1.pdf

thank you but that guide is not applicable to the r26 and r27 which do not have magneto ignitions

[wolfchen75]

Did the solder melt on the wires due to a short circuit?

possibly ? will investigate this idea, should find a burned section

[schrader7032]

That's why I said the paid version of the manual is much better. It covers the battery-coil ignitions.

[jwonder]

Just taking a flier here as you seem to be very proficient, I have two possible ideas:

1) Did you see what the resistance was in the wire to the brushes? It is very possible that you changed the resistance when soldering.

2) Is it also possible that the reason they both came off was that the regulator was shorted and the brushes got overheated? Both coming off at once is very strange indeed. I would test for any continuity between the segments (as outlined in the document Kurt sent you) and then look to the regulator. The document Kurt sent is quite close for the R27 charging system, pass over the ignition portion and go to the charging system portion.

James

[wolfchen75]

This manual might help...it's the early version about the electrical system. There is an updated system which specifically addresses the various models and also has color diagrams.

https://www.snafu.org/restore/uandm_bmw_v1.pdf

I don't seem to be able to find the updated version, an email to his listed address bounced back ? google did not find it either

jeffrey