61 BMW 1983 R100RS/RT Routing Main Wiring Harness

Earlier, I replaced the main wiring harness. I removed all the old harness connections inside the headlight shell and installed the connections of the new harness. You can see how I did that work here:

Main Harness Overview

Here is a short picture summary of how the main wiring harness is constructed. All the details are discussed in the previous link about replacing the main wiring harness.

New Main Wiring Harness from Euro MotoElectrics

New Main Wiring Harness from Euro MotoElectrics

Near Handlebars: Instrument Cluster Plug and Fairing Sub-Harness Plug

Near Handlebars: Instrument Cluster Plug and Fairing Sub-Harness Plug

Near Steering Head: Clutch Switch; Front Brake Switch; GEN Light, Voltage Regulator

Near Handlebars: Instrument Cluster Plug and Fairing Sub-Harness Plug

Near Voltage Regulator/Starter Relay Bracket: Starter Relay Socket; ICU Plug

Near Voltage Regulator/Starter Relay Bracket: Starter Relay Socket; ICU Plug

Near Coil Brackets: Coil Trigger; Coil Power; Rear Brake Switch; Frame Ground; Horns

Near Coil Brackets: Coil Trigger; Coil Power; Rear Brake Switch; Frame Ground; Horns

Near Left Battery Side Cover: Clutch Switch and Turn Signals & Tail Lights

Near Left Battery Side Cover: Clutch Switch and Turn Signals & Tail Lights

Ignition Switch Bundle

Ignition Switch Bundle

Install the Headlight

I installed the top fairing bracket on the steering head. The bracket includes the ears to mount the headlight shell. Then I install the headlight shell in the ears. You can see how I do that here.

Video

I shot a video to show the main wiring harness routing.

VIDEO: 1983 BMW R100RS Routing Main Wiring Harness

Routing The Main Wiring Harness

The main harness exits the bottom of the headlight shell and routes along the frame spine tube.

Routing Harness Along Spine Tube

The main harness goes under the lower triple clamp (aka the lower yoke) and fits between the two front down tubes and in between the gussets that connect the steering head to the spine tube. I start by threading the longest wires first and slowly pull the rest of the harness toward the rear.

Main Harness Cable Exits Bottom Of Headlight Shell

Main Harness Cable Exits Bottom Of Headlight Shell

Main Harness Goes Under Lower Triple Clamp (aka Yoke)

Main Harness Goes Under Lower Triple Clamp (aka Yoke)

Main Harness Goes Between Frame Down Tubes

Main Harness Goes Between Frame Down Tubes

The harness routes between the left side starter relay bracket and right side voltage regulator bracket, then between the coil brackets. The plugs on the end of the main wiring harness that connect to the rear sub-harness, rear brake light switch and the oil pressure and neutral switches extend past the end of the engine block.

Main Harness Goes Between Starter Relay and Voltage Regulator Brackets

Main Harness Goes Between Starter Relay and Voltage Regulator Brackets

Main Harness Goes Between Spine Tube and Reinforcing Tube

Main Harness Goes Between Spine Tube and Reinforcing Tube

Main Harness Goes Between The Coil Brackets

Main Harness Goes Between The Coil Brackets

What Plugs & Terminals Go Where

There are numerous plugs and terminals on the main wiring harness that connect to wiring sub-harnesses or electrical components. I previously mounted many of the electrical components including the voltage regulator, coils, optical-electronic ignition control unit, the oil pressure switch on the engine block and the rear brake light switch.

I’ll start from the front of the main harness and show where each leg goes.

Instrument Cluster Plug

The instrument cluster plug has 12 pins that power the lights and the electronic tachometer.

Routing Instrument Cluster Plug

Routing Instrument Cluster Plug

Instrument Cluster Plug

Instrument Cluster Plug

Routing Instrument Cluster Plug

Routing Instrument Cluster Plug

Plug Inserted Into Instrument Cluster

Plug Inserted Into Instrument Cluster

Fairing Sub-Harness Plug

The fairing lights and the gauges (volt meter and clock) are connected into a sub-harness that plugs into a plug on the main wiring harness.

Fairing Sub-Harness Plug

Fairing Sub-Harness Plug

Front Brake Light Switch & Clutch Lever Switch Plugs

The front brake light switch plug has a GREENRed and two GREEN-Black wires. The clutch lever plug has a BROWNYellow and BROWN wire.

Front Brake Light Switch Sub-Harness Plug (GREEN-Red, GREEN-Black) & Clutch Switch Sub-Harness Plug (BROWN-Yellow)

Front Brake Light Switch Sub-Harness Plug (GREENRed, GREEN-Black) & Clutch Switch Sub-Harness Plug (BROWNYellow and BROWN )

White Plug: Voltage Regulator BLUE (D+) & Starter Relay BLACK (30) Wires

This white plug has two wires and plugs into the other half from the engine that contains the BLUE wire that comes from the (D+) terminal on the diode board and a BLACK wire that goes to terminal (30) on the voltage regulator.

Diode Board BLUE (D+) and Voltage Regulator BLACK (30) White Plug

Diode Board BLUE (D+) and Voltage Regulator BLACK (30) White Plug

Main Wiring Harness Plug Attaches to Engine Wiring Plug

Main Wiring Harness Plug Attaches to Engine Wiring Plug

Starter Relay Plug & Battery (+) Wire With RED End

The main wiring harness includes the starter relay plug. But a BLACK wire with a RED end with a female spade terminal from the battery (+) terminal needs to be plugged into the horizontal hole that is second terminal (87).

Starter Relay Socket with RED Battery Wire The Fits Into Hole In Socket

Starter Relay Socket with RED End Of Battery Wire The Fits Into Hole In Socket

Main Wiring Harness Battery (+) Wire Plugged Into Starter Relay Socket Terminal (87) Hole

Main Wiring Harness Battery (+) Wire Plugged Into Starter Relay Socket Terminal (87) Hole

Electronic Ignition Control Unit White Plug

This white plug routes on the right side of the spine tube. I am not using the stock BMW ignition control unit since I’m using the Euro MotoElectrics optical-electronic ignition system so I will not connect anything to this terminal.

BMW Ignition Control Unit Sub-harness Plug

BMW Ignition Control Unit Sub-harness Plug

Coil Trigger and Tachometer

The terminal with two BLACK wires connects to the lower spade on the right coil. The trigger wire for the optical-electronic ignition also attaches to this terminal.

Coil Trigger And Tachometer Terminal

Coil Trigger And Tachometer Terminal

Horn Wires

There are two BROWN-White wires that go to the left and right side horns.

Right Horn Wire

Right Horn Wire

Left Horn Wire

Left Horn Wire

Frame Ground

The frame ground is the BROWN wires on the ring terminal. The terminal is attached to the frame by the front, left coil bracket bolt.

Frame Ground

Frame Ground

Coil Power (GREENBlue) Wire

The GREENBlue coil power wire goes on one of the spades on the lower terminal of the left coil. The power wire to the optical-electronic ignition control module (RED wire) attaches to a second spade on the same coil terminal.

Coil Power (GREEN-Blue)

Coil Power (GREENBlue)

Main Wiring Harness Coil Power Terminal (GREEN-Blue) Goes On Same Terminal As EME Optical-Electronic Ignition Control Unit Power Wire (RED)

Main Wiring Harness Coil Power Terminal (GREENBlue) Goes On Same Terminal As EME Optical-Electronic Ignition Control Unit Power Wire (RED)

Rear Sub-Harness Plug And Oil Pressure & Neutral Switch Plug

The rear sub-harness plug connects to the rear wiring sub-harness to power the brake light, running light and rear turn signals. The smaller plug has a BROWN-Black wire that goes to the neutral switch and BROWNGreen wire that goes to the oil pressure switch and plugs into a sub-harness that connects to those switches.

Rear Sub-Harness Plug (Large) and Neutral & Oil Pressure Switch Plug (Small)

Rear Sub-Harness Plug (Large) and Neutral & Oil Pressure Switch Plug (Small)

Rear Brake Light Switch Plug

This plug has a GREENRed and a GREEN-Black wire. It plugs into the rear brake light switch sub-harness.

Rear Brake Light Sub-Harness Plug

Rear Brake Light Sub-Harness Plug

Handlebar Controls

Although these are not directly attached to the main wiring harness, they too come from the headlight shell. I’ll attach them to the handlebars when I mount it.

Right Handlebar Control

Right Handlebar Control

Left Handlebar Control

Left Handlebar Control

Ignition Switch Wires

These four wires are not directly attached to the main wiring harness but they come from the headlight shell. I’ll attach them when I install the dash panel in the fairing.

Ignition Switch Wires

Ignition Switch Wires

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.