Location of Diodes on Bike

[Breezerider]

I'm having a pesky starting problem with the starter cutting out right after pressing the start button.  It is a problem that came and went and then grew in severity over a year so now I can only bump start the bike, meaning I don't think anything blew or broke but slowly self destructed.  All wiring connections on the bike have been cleaned and greased, so I don't think there is a corrosion problem on any of the spade connectors.

I also have the charge light acting as my neutral indicator light and no neutral light.  I replaced the starter relay, but no fix.  Looking at the wiring diagram, it seems likely that one or both of the diodes, apart from the ones in the rectifier, are at fault.  One diode connects to the neutral indicator switch and the other to the charge, neutral and oil pressure lights.  One looks like it could be in the headlight nacelle, but the other could be anywhere in the harness.  Anyone know where it is located?  Anyone have any insigts into this problem?

[montmil]

...One looks like it could be in the headlight nacelle...

Providing the model and year of your bike may likely generate a few more responses.
Monte

[Bengt_Phorqs]

If you have the 9 tooth Valeo starter they have a tendency for the magnets inside the starter case  to come loose.  Sometimes it will work and sometimes it won't.  Rick Jones at Motorad Elektrik can rebuild it I'm told.  I had the guys at Grass Roots BMW in Cape Girardeu, MO rebuild mine.  They had helped me out when I broke down in Tennessee in '08 at the Shiloh rally.  The repair was less than $200.

[nhmaf]

IF you have a 1985 or later model, I believe that BMW used starter relays with built in diodes in the bikes.  Prior to that, I think that the clutch/starter diode is in a housing in the headlight or on the circuit board inside the headlight shell (pre-1980?).  I am not certain, but I think that the R65 bikes had the integrated diode in the starter relay before the other bikes.   Look closely at your original starter relay to see if it has a diagram on it indicating a diode connection between terminal 86 and 86A..

Starter Relays
12 41 1 350 775 [A] /5 (GN/SW-->15, three RT-->30, BR/SW-->31b, SW-->87, two BL-->D+)

61 31 1 357 104 /6 ('74: SW, BR/GE, three GN/SW, two RT, two BL; later wired like /7?)

61 31 1 243 207 [C] '77 to '84 (30, 85, 86, 87, 87 w/ Clutch/Neutral diode in Headlight Contact Board)

61 36 1 389 105 [D] '85 on & all 'GS, R45, R65 (30, 85, 86, 86a, 87 w/ Clutch/Neutral diode 86-86a)

[Bob_Roller]

We kinda need to know what year bike you have .

Have you checked the light bulb for the neutral indicator ?

If you have a '79 or '80 model year bike, the starter diode is in the wiring harness, not having that model year bike, I can't comment on it's location .

If the wiring diagram is any indication, it's not in the headlight area, more like in the main wiring harness, near the start relay, it should be a round part about 3/8 ths of an inch in diameter and about 2 inches long, it has push on spade type connectors and most likely wrapped in black cloth tape .

The diode you see in the wiring diagrams in the tachometer, is a light emitting diode used on the '79-80 model year bikes, it was an over rev indication .

There's one more possibility with your starter problem, there is a switch activated by the clutch lever .

Follow the wires from the clutch lever, and when you get to the connector, pull it apart, and use a piece of bare wire to jumper the two connectors on the bike side of the wires, then try to start the engine .

[Breezerider]

...One looks like it could be in the headlight nacelle...

Providing the model and year of your bike may likely generate a few more responses.
Monte

Yah, for sure, duh, goes to slap forehead, misses, falls out of seat.  It's a 1979 R65.  The date of manufacture was actually 1978 according to the frame number

[Bob_Roller]

Starting with a manufacture date of 09/81, a lot of changes occurred with the R65, and in some instances, it makes a real difference in working on and troubleshooting the bike .