61 BMW 1977 R100RS Remove Wiring Harness, Instruments & Electrical Components

Remove Turn Signals, Parking Light, Head Light, Instruments, Ignition

I show how I remove the body panels, front turn signals, parking light, head light, dash, instruments and ignition switch, rear fender, rear tail light and turn signals in this write-up.

There were changes made in the wiring to install heated grips and VDO oil pressure and temperature gauges. However, none of these were working: the wiring to the gauges had been cut and the heated grip wiring had been patched and disconnected.

Remove Electrical Components

The bike was updated with dual plug heads and a Dyna III electronic ignition. The stater relay, horn relay and voltage regulator are stock. Removal is straight forward. I took pictures and labeled wire ends to simplify installation.

Remove Voltage Regulator

This is the large rectangular can on the right side of the bike under the gas tank. There is a triangular plug that goes into a socket in the bottom. The wires come from the alternator inside the front cover. I remove the triangular plug and unscrew the Allan head bolts to remove the voltage regulator from its bracket.

Voltage Regulator

Voltage Regulator

Voltage Regulator Triangular Plug

Voltage Regulator Triangular Plug

Voltage Regulator Wires Come From Top of Front Engine Cover

Voltage Regulator Wires Come From Top of Front Engine Cover

Remove Dyan III Coils and Ignition Module

The bike has dual plug heads and uses the Dyna III two port coils (red). The green/blue wire from the main harness plugs into the outer lug of the left coil. The red wire from the Dyna III ignition module plugs into the other spade of the same lug. A second lug toward the inside of the bike has a black jumper wire that plugs into the inside lug of the right coil. These are 6 volt coils, so the black wire puts them in series for the 12 volt ignition system.

Dyan III Coil Left Side-Blue/Green and Red Wires

Dyan III Coil Left Side-Blue/Green and Red Wires

Dyna III Left Coil Connections

Dyna III Left Coil Connections

The right side coil has a brown wire from the ignition module that plugs in a spade on the outside lug. Note the black ground wire from the ignition module is connected to the right side top engine cover allan head bolt per Dyna instructions.

Dyna III Right Side Coil-Ignition Module Brown Wire

Dyna III Right Side Coil-Ignition Module Brown Wire

Dyna III Right Coil Connections-Note Black Jumper to Left Coil

Dyna III Right Coil Connections-Note Black Jumper to Left Coil

The ignition module has six wires: a bundle of red, brown and black that go to the coils and ground to the engine and two other wires, red and white, that connect to the hall effect sensor (aka, points) inside the front cover. I remove the module and unplug the two red and white wires from the leads going to the hall effect sensor.

Dyna III Ignition Wires

Dyna III Ignition Wires

Dyna III Ignition Module

Dyna III Ignition Wires

Remove Starter and Horn Relay Sockets and Remove Wires

These are located under the gas tank on the left side opposite the voltage relay.

Horn (Left) and Starter (Right) Relays and Sockets

Horn (Left) and Starter (Right) Relays and Sockets

Horn Relay (Right) Starter Relay (Left), From Top Showing Bosch Part Nos.

Horn Relay (Right) Starter Relay (Left), From Top Showing Bosch Part Nos.

Relays and Terminal Blocks, Side View

Relays and Sockets, Side View

In front of the relay sockets is a white plastic connector with blue wires. I unplug these.

Starter Relay-Blue Wire with Separate Connector

Starter Relay-Blue Wire with Separate Connector

I unplug the relays from the sockets There is a lot of corrosion on the relay prongs and inside the sockets where the female terminals are located. I plan to replace the relays. I remove the female terminals from the sockets so I can clean them up.

Starter Relay Contact Corrosion - Green and Gruesome :-)

Starter Relay Contact Corrosion – Green and Gruesome 🙂

Relay Terminal Blocks, Top View. Both Relays Use the Same Terminal Block

Relay Sockets, Top View. Both Relays Use the Same Socket Design

Horn Relay Wiring (Left) Starter Relay Wiring (Right) Insert Into Bottom of Relay Blocks

Horn Relay Wiring (Left) Starter Relay Wiring (Right) Insert Into Bottom of Sockets

Starter Relay Wiring

Starter Relay Wiring

Horn Relay Wiring (Right)

Horn Relay Wiring (Right)

The sockets have a keyed side so they can connect to each other. I slide them apart so I can remove the wires going into the bottom of the sockets easier.

Separating Relay Terminal Blocks

Separating Relay Sockets

Horn Relay(Left) Starter Relay(Right) Separated

Horn Relay(Left) Starter Relay(Right) Sockets – Back Side

Starter Relay (Top) & Horn Relay (Bottom) Separated

Starter Relay (Top) & Horn Relay (Bottom) Sockets Separated

I use a small, thin, flat blade screw driver to compress the tab on the side of the female terminals inside the socket so I can remove them. As shown here, the slot is the small rectangular hole centered next to the longer slot the female terminal fits into.

Terminal Block Plug-Top Side Showing Slots Relays Plug Into

Relay Socket-Top Side Showing Slots Relays Plug Into

I find pushing the screw driver into the slot and twisting it a bit while pulling on the wire makes it pretty easy to remove the terminals from the socket.

Remove Wire From Terminal Block with Small, Thin Flat Blade Screw Driver

Remove Wire From Relay Socket with Small, Thin Flat Blade Screw Driver

A Slight Twist Flattens Tab on Terminal Pin

A Slight Twist Flattens Tab on Terminal Pin

As I remove the wires from the sockets, I make a diagram showing the location and color of each wire so it will be easier to connect them again. This is my short-hand for the colors:

  • BR-Brown
  • BL-Black
  • BLU-Blue
  • GR-Green
  • RD-Red
  • WH-White
  • YL-Yellow
Horn Relay Socket Connections

Horn Relay Socket Connections

Starter Relay Socket Connections

Starter Relay Socket Connections

NOTE:
Some of the wires I labeled as “Brown” (BR) are actually red. The insulation had discolored. I figured this out when I put the cleaned wires back into the sockets. See the write-up about installing the wiring and electrical components where I have a video showing how to use the wiring diagram and the terminal numbers on the sockets to ensure the correct wire goes into the correct hole in the socket.

The starter relay has wires from the main wiring harness, the (+) battery cable and from the alternator inside the front engine cover via the front slot of the inner cover. The horn relay has a jumper from the starter relay socket, a ground wire, a black wire going to the horns and a wire coming from the main harness that goes to the horn button.

Starter Relay Wire from Battery (+) Cable-Grungy

Starter Relay Wire from Battery (+) Cable-Grungy

Horn Relay (Left) & Starter Relay Wires (Right)

Horn Relay (Left) & Starter Relay Wires (Right)

Starter Relay Wires Removed (Brown Wires are Really Red)

Starter Relay Wires Removed (Brown Wires are Really Red)

Remove Rear Wiring Sub-harness

The wiring to the brake light and turn signals goes through a separate sub-harness that plugs into the main harness near the left side of the battery box.

Rear Sub-harness Plug

Rear Sub-harness Plug

The sub-harness routes inside the rear sub-frame via a hole near the left handhold and a second hole at the back of the sub-frame in the middle.

Remove Rear Tail Light and Turn Signals

This shows how I removed the rear tail light assembly and the turn signals from the rear wire harness.

With the wires disconnected from the tail light and turn signals, the rear sub-harness can be pulled through the sub-frame to remove it. Since I am going to clean the terminals on the rear sub-harness, I remove the male pins from the rear sub-harness and pull it out the rear hole using the round male terminal pin removal tool. I make a sketch of the pin locations in the plug before removing them.

Rear Sub-harness Plug

Rear Sub-harness Plug

Rear Sub-harness Plug Pin Diagram

Rear Sub-harness Plug Pin Diagram

Using Male Round Pin Removal Tool To Remove A Pin

Using Male Round Pin Removal Tool To Remove A Pin-Insert, Rotate and Pull on Wire

Male Terminal Pin Removed from Rear Sub-harness Plug

Male Terminal Pin Removed from Rear Sub-harness Plug

Rear Harness Terminals Removed From Plug

Rear Harness Terminals Removed From Plug

Here is the rear sub-harness with tail light attached with the rear sub-frame removed.

Sub-frame with Rear Sub-harness Removed

Sub-frame with Rear Sub-harness Removed

Remove Rear Brake Light Switch

There are two wires that go to the rear brake light switch. I remove the rubber cover, then the two screws securing the switch and remove the two wires.

Remove Clutch Switch & Neutral Switch Sub-harness’

The clutch lever has switch and a small sub-harness that attaches to a plug in the main harness near the left side of the steering head. There is also a short sub-harness that connects to the neutral and oil pressure switches. This plugs into the main harness near the left front foot peg. I unplug these sub-harness’.

Front Clutch Switch Connector Plugs Into Main Harness Near Left Side of Steering Head

Front Clutch Switch Connector Plugs Into Main Harness Near Left Side of Steering Head

Remove Main Wire Harness

With all the electrical components and sub-harness’ disconnected from it, I remove the main wire harness. I snip the zip ties securing it to the frame with wire cutters. As I pull it forward, I label the branches and ends of wires with the component they connect to so it will be simple to reinstall it.  When the main harness hangs down beneath the headlight bucket, I remove the headlight bucket with the main wiring harness and handle bar switch wire harness’ attached.

Wire Harness & Electrical Components Removed

Wire Harness & Electrical Components Removed

Wire Harness & Electrical Components Removed

Wire Harness & Electrical Components Removed

Various Wire Harness’

Here is a summary of the various wire harness’ I removed.

Main Wire Harness

Here is a photo of the main harness showing what the branches connect to.

Main Wire Harness Removed with Labels On Branches

Main Wire Harness Removed with Labels On Branches

Fairing and Instrument Panel Sub-harness

Here is the fairing and instrument panel sub-harness. The ignition switch wires are part of the main harness.

Fairing & Instruments Wire Harness

Fairing & Instruments Wire Harness

Heated Grips Sub-harness

This is the heated grips on-off switch and sub-harness.

Heated Grips On/Off Switch Attached to Sub-harness

Heated Grips On/Off Switch Attached to Sub-harness

Heated Grips Sub-harness

Heated Grips Sub-harness

Rear Sub-harness

And the rear sub-harness with the tail light and turn signals still attached to it is shown below. Note that I removed the plug that goes on the end of this harness so I can clean the pins.

Sub-frame with Rear Sub-harness Removed

Sub-frame with Rear Sub-harness Removed

Rear Sub-harness with Plug Inside Rear Sub-frame

Rear Sub-harness with Plug Inside Rear Sub-frame

 

5 thoughts on “61 BMW 1977 R100RS Remove Wiring Harness, Instruments & Electrical Components

  1. Rear Sub-harness Plug Pin Diagram

    one comment as i glance thru this brook is

    i always make reference to which end of the ‘plug’ i’m looking @ :
    male /female back side / front side
    or plug in side / wire side … as i write down wire color and location because it could be depending on the plug type) opposite from the wrong end. especially when shooting trouble.

    cause @ least for me 6 hrs, 16 days or 6 months later i’ll need that info again and it may not appear to be clear to me … … then.

    • Wow ! was that R100 still running or sitting with all that corrosion.? I think you are just the Man I need to ask a question . I am a Machinist who is challenged in electrical areas. On occasion I do not get a green neutral light when I am in neutral (not false neutral) No doubt I need to change the neut. switch which I can do (sometime) . Meanwhile I would like to know how to bypass the system and get going when this happens. I realize I will not have starter protection in the event I hit the wrong button when riding. Hope you can help, thanks Henry 1980 R80/7 also 1967 R50/2

      • Hi Henry,

        Amazing that it was running before I started the rebuild.

        I’m afraid I don’t have any advice on how to bypass the neutral switch. That said, sometimes the pins in the large rubber connection to the back of the instrument cluster get dirty and a cleaning fixes flaky lights. Also, the internal flexible circuit board is prone to having copper tabs fracture where they bend into the hole for the light bulb sockets.

        You may want to look at these potential problems if you haven’t already.

        This write-up shows a repair I made to the instrument circuit board.

        62 BMW 1983 R100RS Repair Instrument Circuit Board Foil

        I hope this helps.

        Best.
        Brook.

  2. Pingback: 1977 BMW R100RS Cleaning Up The Electrical Wiring and Components | Motorcycles & Other Musings

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