No lights or Start - 1980 R65

[Redbaron]

1980 BMW R65. I just replaced steering bearings, rebuilt front forks,rebuilt front ATE brake.  I rebuilt the Bings, and it was running great before I did the front end work. I spent 9 hours today trying to find the electric issue. NO GO. I took apart, cleaned and tested wires going to start button and kill switch. No power to these switches and wire continuity is good. I inspected fuses and checked continuity to all wires to/from fuses. I inspected all wires and relays under tank (horn, headlt, starter). I inspected all wiring harness wires, wires going to headlight, and rear lights. I took apart, inspected, cleaned ignition switch. Transmission is in neutral. I tried jumping bike with car...nothing. I used test light and there is power to starter and power on (red wire) that goes into what I think is headlight relay. I cannot identify the 3 relays found under the tank. This is a 1980 R65 which has several differences then older R65's. The relays are lined up single file on the main frame tube along with the voltage regulator. Please let me know if you have a good reference for the 1979-80 R65 electrics. I have a Clymers manual but it doesnot  detail start problems or wiring issues.  I have searched the internet for sites/info on the start relay, nothing, not even something identifying its location.  Please let me know what you think I should check next. Thanks

[Bob_Roller]

I have second generation R65's . Over the years I've heard from owners of first generation R65's that there is a main grounding point for a lot of circuits on the forward ignition coil bracket causing issues.
 Might want to check this out seeing as you've been working in this area .
Hope you find the cause !!😁

[georgesgiralt]

Hi !
You seem to have power to various needed components because you tested that with the test bulb.
But do you have enough of it ?  The consumption and needs of a low wattage bulb is way different from the needs of a starter motor.
So i would check the ground on the chassis just to be sure.
Also, you can jump start the starter motor by energizing the coil with a wire between the positive from the battery and it.  You'll check that it gets enough juice to run...
Troubleshooting electrical issues is not that fun. You should try to isolate parts of the wiring and check if they run properly.
I may have a paper schematics for your bike but are many many miles away from home. So if you can't find the fault report back and I'll check when I get back next week end.

[Barry]

1980 is a transitional year but If it's a 1st generation R65  then this is the best wiring diagram available.

[Barry]

The relays are lined up single file on the main frame tube along with the voltage regulator.

This is what my 1st generation model looks like - only two relays and the voltage regulator. Ignore the black box which is an electronic  points booster.

[Redbaron]

Hey Barry thanks for the info.  This is photo of my relays. do you know which one is starter relay?

[Barry]

I can't see clearly in the picture but it looks to be the one marked horn. You should be able to identify the starter relay by comparing the wire colours with the diagram. Most of the wires are either 0.75mm2 or 1.0mm2. The starter relay should have a thicker red wire that's 2.5mm2

[Barry]

One of the possibilities of a 1980 model is they are some times a parts bin special i.e. some features of the older model and some of the new. 

The dome top carbs and type of air box are from the new model and the coils are from the old. i'd need to see s picture of the whole bike to identify other features

[Redbaron]

Hey Barry thanks so much for identifying the starter relay. The metal relay marked horn is in fact the starter relay, it is the only one with the big fat red wire. This wire has power coming into relay. How can I test this relay?

[georgesgiralt]

You can test it by bridging it's input and output and check if the starter motor runs properly. Basically, a relay is a switch
Be careful because these fat red wires are not fused, so if you make a short... the bike might burn ....
And triple check the wiring to understand which wires to jump.
Also, your harness is very old. I bet the wires are not supple anymore, and that the copper inside is not shiny but some sort of corroded thing.
Mine did that and was like that. So my headlight was so feeble I could not see the front mudguard in the night.
I've since bought a new harness and things have improved vastly ... (the cost is quite high but I do not regret it)...

[Barry]

If you want to test if the starter relay functions remove it and apply 12 volts to the relay coil terminals which are marked 85 and 86.

85 is -ve and 86 is +ve.   You should hear the relay click and you should have continuity between 30 and 87



or to test it in situ as Georges suggests bridge 30 to 87

[Redbaron]

i do not have power on red wire going into ignition key switch and no power on wires going into start button and kill switch. Battery is 12.75 volts.

[Redbaron]

I solved the problem! Red wire going to ignition key switch bad. I ran test wire from battery to ignition and it starts! Now I have to find best spot to splice into another positive red wire. Any suggestions would be appreciated. Thanks for all the comments which guided me to find this problem.

[georgesgiralt]

Hello,
Glad you found the problem.
But, as the red wire from the battery to the ignition switch is quite hefty, I doubt it has cut itself out... 
Do you by any chance have removed the battery and forgot to plug it in back upon reinstalling ? Because I think there are TWO wires going to the positive post on the battery, the huge charge/starter motor one and a smaller gauge one which powers everything else...
I did, once, this mistake..... So, just asking.
Could also been the wire got disconnected at the ignition key if you have disturbed the wiring harness

[Redbaron]

I think the fat red wire is faulty somewhere inside the harness . I ran the new red wire from battery terminal along harness and then directly to ignition switch.