61 BMW 1977 R100RS Refurbish and Install Wiring & Electrical Components

I show how I remove the main wiring, various sub-harness’, instruments and the electrical components in this write-up.

Based on the amount of oxidation and the cracks in the outer sheath, not to mention the age of the wiring harness, it needs to be refurbished or replaced. That said, the 1977 R100RS main wire harness (part#  61 11 1 243 222) is a one year only harness and is no longer available from BMW. I did find one source for the main wire harness, Todd Millican, at “Brits and Beemers“, but at a quote of $500 (which is not unreasonable IMHO due to the labor required to make a quality harness which is what Todd does) I can afford to invest a lot of my time at my current hourly rate [about $0.00 if I don’t count the beer and who counts the beer 🙂 ] and see if I can’t get it back into shape. The work I did includes:

  • Remove pins from and terminals from all connectors, clean and reinstall.
  • Repair tears in the outer black protective sheath of the harness’.
  • Test the horns (they still worked). Clean and repaint them to freshen them up.
  • Replace damaged spade terminals with new ones.
  • Replace torn/missing rubber sleeves over the outer sheath where individual wires and branches exit the harness with shrink tubing.
  • Clean outer sheath and all exposed wire insulation.
  • Replace the starter and horn relays, voltage regulator, the oil pressure switch, and the neutral switch.
  • Install electrical components
  • Install headlight with main harness and connect to electrical components
  • Install fairing & dash instrument sub-harness and connect to instruments, ignition switch, turn signals and parking light
  • Install rear sub-harness, tail light and turn signals

The inside of the headlight shell showed no rust and all the internal connections are clean and not oxidized which is welcome news. That’s one reason I decided not to replace the harness and invest to refurbish the wiring.

The VDO oil pressure and temperature gauges have a sub-harness the goes to contacts inside the headlight shell. The harness had been cut and I don’t plan to use the gauges at the moment, so I remove these wires from the terminal board inside the headlight shell.

VDO Oil Gauge Connections to Terminal Board Inside Headlight Shell

VDO Oil Gauge Connections to Terminal Board Inside Headlight Shell (Grey-Black, Green-Black)

Resources

There are several resources on Bob Fleischer’s site about airhead wiring:

I have both the Haynes and Clymer manuals and both have wiring diagrams. Of the two, I prefer the Haynes and it’s color wiring diagrams that are easier to read. That said, there are differences in both manuals from how the wiring was actually done inside the headlight shell. By comparing the connections in the headlight shell with the two diagrams, I can see what wires go where. I did that to confirm no one had futzed with the wiring inside the headlight shell. It looked to me that the main harness and handle bar switch harness connections inside the head light shell go where they ought to.

Parts

Here are the parts I installed for this work. I sourced most of them from Euro Motoelectrics and show their part numbers. The BMW part number is in { } in the description. Due to the age and condition of the horn and starter relays, and the voltage regulator, I chose to replace them. The oil pressure sender had been replaced by a VDO oil pressure gauge and sender which I currently don’t plan to use so I got a new oil pressure switch I got a new neutral switch for the transmission. I replaced the (+) battery cable when I refurbished the starter motor and have a new (-) ground cable. Electrical reliability should be improved with the refurbished wire harness’ and new components.

Part #                  Description                                            Qty
BCK-475216 Battery Cable Kit (4 Gauge) – BMW R Airhead / Negative {BMW # 61 12 1 244 475} Positive {BMW#  61 12 1 243 216 or 61 12 1 243 874} 1
BAT-12V30 Battery 12V/30AH – WestCo AGM
{BMW# 61 21 1 459 650]
1
NPS-097 Neutral Position Switch – BMW R Airhead {BMW# 61 31 1 243 097} 1
61 31 1 355 262 GASKET RING – A 12,2 X 20-AL 1
OPS-414 Oil Pressure Switch-BMW R Airhead
{BMW# 61 31 1 243 414}
1
OPS-414CW Oil Pressure Switch Crush Washer
{BMW #61 31 1 243 414,
61 31 1 354 274, 12 61 1 277 642}
1
REL-588 MINI-RELAY (to 09/78) Horn Relay
w/ resistor BOSCH
{BMW# 61 31 1 373 588}
1
REL-207 Relay-Starter BMW R Airhead / Bosch
{BMW# 61 31 1 243 207}
1
EDL1-ALTKIT 107 INCLUDED IN KIT: BMW Voltage Regulator: {BMW# 12 32 1 244 409} 1

Tools

Nitro Tape – I got this from Motion Pro. It is a thin silicone tape that molds to itself. I like it for repairing tears in the outer protective sheath around a bundle of wires.

Motion Pro Nitro Tape for Repairing Wire Harness Outer Cover Tears

Motion Pro Nitro Tape for Repairing Wire Harness Outer Cover Tears

Cleaning Solution – I use a white vinegar with salt solution to remove corrosion from the terminals. After soaking for a few minutes, I dip the terminals in a solution of baking soda to neutralize the vinegar. I brush the terminals with a brass brush to remove the loosened crud.

Vinegar and Salt Solution For Cleaning Contacts

Vinegar and Salt Solution For Cleaning Contacts

Baking Soda Solution Neutralizer

Baking Soda Solution Neutralizer

Round Male Pin Removal Tool – This tool compresses the prong on round male terminals so they can be removed from a plug. I got it from Mouser Electronics, Inc (Part# 571-4656441)

Male Round Pin Terminal Removal Tool

Male Round Pin Terminal Removal Tool

Male Pin Round Terminal Removal Tool

Male Pin Round Terminal Removal Tool

Female Spade Terminal Removal-Screw Driver & Pick – I use a small, thin blade screwdriver and/or a pick to compress the prong on these terminals so they can be removed from the sockets the horn and starter relay plug into and various other terminals that had a plastic housing around the terminals.

Small Thin Blade Screw Driver to Remove Relay Terminal from Plug

Small Thin Blade Screw Driver to Remove Relay Terminal from Plug

Pick Used to Remove Neutral Terminal From Plastic Cover

Pick Used to Remove Neutral Terminal From Plastic Housing

Wire Strip & Terminal Crimp Tool – This tool strips insulation without nicking the wire and crimps the end of a female or male spade terminal. I also solder them.

Crimp, Strip Pliers

Crimp, Strip Pliers

Soldering Iron, Flux, Solder – These are used to solder a new terminal on a wire. Even though the solder has some flux in it, I like to add flux to the joint and heat it up before applying the solder to ensure a good clean solder joint.

Flux, Solder Gun and Solder

Flux, Solder Gun and Solder

Flux For Copper Wiring

Flux For Copper Wiring

Multi-Meter – I use it to test for continuity, to trace a wire in a harness, and to be sure the resistance of the wire is low to prove the wire is not broken somewhere in the harness. I have collected several over the years including the expensive Fluke meter which was a gift 🙂

Radio Shack Multi-Meter

Radio Shack Multi-Meter $$

Fluke Multi-Meter $$$$

Fluke Multi-Meter $$$$

Clean & Repair Wiring Harness’ & Terminals

The terminal connections and the plug terminals all need cleaning. Many of  them are green with corrosion.

Starter Relay Contact Corrosion

Starter Relay Contact Corrosion

Starter Relay Wire from Battery (+)-Green and Grungy

Remove Terminals From Plugs

I use a small, thin blade screw driver and a pick to flatten the tab holding the female spade terminals in the horn and starter relay so I can remove them. Some of the connectors with one or two wires have a plastic cap and a pick works to flatten the tab on the terminals without cracking the plastic. The rear sub-harness uses round pin terminals and I use a special tool for removing them. It flattens the two tabs on the side of the pin so it can be removed from the plastic plug.

Using Small Thin Flat Blade Screwdriver To Remove Female Terminal from Relay Socket

Using Small Thin Flat Blade Screwdriver To Remove Female Terminal from Relay Plug

Using Tool To Remove Round Terminal Pin

Using Tool To Remove Round Terminal Pin

Terminal Pin Removed from Rear Harness Plug

Terminal Pin Removed from Rear Harness Plug

Using Pick to Remove Neutral Switch Terminal From Plug

Using Pick to Remove Neutral Switch Terminal From Plug

Neutral Switch Terminal Removed

Neutral Switch Terminal Removed

Pick Used to Remove Neutral Switch Terminal From Neutral-Oil Pressure Switch Plug

Pick Used to Remove Neutral Switch Terminal From Neutral-Oil Pressure Switch Plug

Using Pick To Remove Pins From Fairing-Instruments Sub-Harness Plug

Using Pick To Remove Pins From Fairing-Instruments Sub-Harness Plug

Cleaning Terminals

I dip the terminals in a white vinegar and salt solution for 3 to 5 minutes. This dissolves much of the corrosion off the terminals. Then I put them into a baking soda solution to neutralize the acetic acid in the vinegar. Then I use a brass wire brush to polish each terminal. It takes time but the corrosion is gone.

Starter and Horn Relay Terminals-Green and Grungy

Starter and Horn Relay Terminals-Green and Grungy

Soaking Terminals in Vinegar and Salt Solution

Soaking Terminals in Vinegar and Salt Solution

Baking Soda Neutralizer Solution

Baking Soda Neutralizer Solution

Cleaned Starter and Horn Relay Terminals

Cleaned Starter and Horn Relay Terminals

I use a small round file to polish the inside of the round edges of the female spade terminals. The end of the file is serrated and works as well.

Small Round File Cleaning Inside of Terminal Rounded End

Small Round File Cleaning Inside of Terminal Rounded End

Small File Handle Serrations Work For Cleaning Inside Terminal Rounded End

Small File Handle Serrations Work For Cleaning Inside Terminal Rounded End

The tab on the side of the spade terminals and round pin terminals gets flattened to remove the terminal. I use the small pick and screw driver to gently pry the tab so it is exposed and will lock the terminal in the slot of the plug.

Popping Out Tab on Female Terminal

Popping Out Tab on Female Terminal

Popping Out Tab On Round Terminal Pin

Popping Out Tab On Round Terminal Pin

Remove & Reattach Rubber Cover From 90 Degree Terminals

These female terminals have a rubber sleeve that wraps around the terminal. These type of terminal are used for the wires that plug into the ignition switch and other connections. I slip a thin blade screw driver under the edge of the rubber where the two ends are sealed and carefully peel the ends apart.

Seal of Ends of Rubber Boot On 90 Degree Terminal

Seal of Ends of Rubber Boot On 90 Degree Terminal

Removing 90 Degree Terminal Rubber Boot

Removing 90 Degree Terminal Rubber Boot

Rubber Boots Removed From Ignition Switch Wiring Terminals

Rubber Boots Removed From Ignition Switch Wiring Terminals

After I clean them, I reattach the rubber boots and stick the ends back together using 3M “Gorilla Snot”.

3M "Gorilla Snot" Adhesive

3M “Gorilla Snot” Adhesive

Sealing Seam of Rubber Boot with 3M "Gorilla Snot"

Sealing Seam of Rubber Boot with 3M “Gorilla Snot”

Replace Damaged Terminals

One of the terminals to the starter relay got mangled when I was removing it and the terminal for the oil pressure switch had been replaced with a ring terminal to attach it to the VDO pressure gauge.

Bent Horn Relay Ground Terminal

Bent Horn Relay Ground Terminal

I illustrate the procedure with the oil pressure switch spade terminal. The difference for the starter relay terminal is the omission of the shrink tubing over the crimped end of the terminal.

I cut the old terminals off and install new female spade terminals.

New Female Terminal with Tabs For Crimping

New Female Terminal with Tabs For Crimping

I strip the insulation using the stripper-crimper so there is about 1/8 inch of bare wire. I thread a smaller diameter shrink tube over the wire that I will heat to shrink around the wire and the where I crimp it.

Then I crimp the terminal in two places, over the insulation and over the bare wire. I use needle nose pliers to shape the two tabs on the terminal so they are rounded and the ends centered over the wire and use the crimper anvil to bend them securely around the insulation and the wire.

Crimping Anvils

Crimping Anvils

Oil Pressure Spade Crimped to Wire in Two Places

Oil Pressure Spade Crimped to Wire in Two Places

Then I solder the bare wire to the terminal to ensure a good connection. I put some flux on the wire and heat it with the soldering iron to clean the wire,

Flux for Copper Wires

Flux for Copper Wires

Flux on New Oil Pressure Spade Ready To Heat

Flux on New Oil Pressure Spade Ready To Heat

Solder on New Oil Pressure Spade

Solder on New Oil Pressure Spade

I slip the small diameter shrink tube over the terminal end where I crimped the wire and heat it. Then I slip a larger diameter shrink tube over the spade end of the terminal so it covers all of the spade and then heat it to shrink it around the spade.

Shrink Tube Over Crimped End of New Spade Terminal

Shrink Tube Over Crimped End of New Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Repair Outer Sheath

The outer sheath on the main and a couple of the sub-harnesses have tears. Also, several of the rubber seals installed where branches and wires exit the harness are degraded and torn.

I use Motion Pro “Nitro Tape” to repair the tears in the outer sheath. The tape fuses to itself when stretched. I cut a piece and then tightly wrap it around the outer sheath starting about 1 inch before the tear and sending 1 inch after. I use two layers. I use it the same way to replace torn rubber seals where large branches exit the main harness.

First Layer of Nitro Tape Repair to Outer Sheath of Main Harness

First Layer of Nitro Tape Repair to Outer Sheath of Main Harness

Main Harness Outer Sheath Repair with Nitro Tape

Main Harness Outer Sheath Repair with Nitro Tape

There is a rubber sleeve wherever a branch or wire exits the harness bundle. Many of these have torn or come loose. I use shrink tubing and nitro tape to replace these.

This Original Rubber Seal on Outer Sheath Is Still In Good Condition

This Original Rubber Seal on Outer Sheath Is Still In Good Condition

Degraded and Torn Outer Sheath Rubber Seals

Degraded and Torn Outer Sheath Rubber Seals

Adding Shrink Wrap to Seal Outer Sheath Where Wires Exit

Brake Reservoir Level Terminals with Shrink Tube Repair To Outer Sheath

Adding Shrink Tube Replace Rubber Seal Over Outer Sheath

Brake Reservoir Level Terminals with Shrink Tube Repair To Outer Sheath

Brake Reservoir Level Terminals with Shrink Tube Repair To Outer Sheath

Brake Reservoir Level Terminals with Shrink Tube Repair To Outer Sheath

Install New Turn Signal and Parking Light Rubber Boots

The original boots have lost their elasticity and are torn so I replace them.

Old Turn Signal Rubber Boot

Old Turn Signal Rubber Boot

They were secured with rubber sleeves. I use three pieces of shrink tubing of increasing diameter to secure the new rubber boots to the wiring harness.

Small and Medium Diameter Shrink Tubing For Securing Rubber Boot

Small and Medium Diameter Shrink Tubing For Securing Rubber Boot

Largest Diameter Shrink Tubing Goes On Last

Largest Diameter Shrink Tubing Goes On Last

Turn Signal Terminals Inside Rubber Boot

Turn Signal Terminals Inside Rubber Boot

Largest Shrink Tubing Over End of Rubber Cover

Largest Shrink Tubing Over End of Rubber Cover

Three Sizes of Shrink Tubing To Secure Rubber Cover For Front Turn Signals

Three Sizes of Shrink Tubing To Secure Rubber Cover For Front Turn Signals

Test Ignition Switch

The ignition switch wires come out of the back of the headlight shell and connect to terminals on the back of the ignition switch that mounts in the dash.

Ignition Switch Wires Come Out of Rear of Headlight Shell

Ignition Switch Wires Come Out of Rear of Headlight Shell

Here is a short video showing how I test the ignition switch.

VIDEO: Testing The Ignition Switch

Install Main Harness Terminals into Horn & Starter Relay Sockets

It’s easier to install the wires from the main harness that plug into the horn and starter relay sockets with the harness out of the bike. There are other wires that go into these sockets that come from the (+) battery cable and the alternator and I’ll put those into the sockets after I thread the main harness into the frame.

The bottom of each relay has numbers next to the pins that correspond to the numbers in the wiring diagram.

Starter Relay Terminal Numbers on Bottom

Starter Relay Terminal Numbers on Bottom of Relay

Horn Relay Terminal Numbers on Bottom

Horn Relay Terminal Numbers on Bottom of Relay

 

Starter and Horn Relay Pins Numbers Shown in Wiring Diagram

Starter and Horn Relay Terminal Numbers Shown in Wiring Diagram

I also drew diagrams of where the wires were plugged into bottom of the sockets when I removed them. But, the red insulation had weathered to brown and that confused me when I looked at the wiring diagram colors when it came time to reassemble the wiring into the relay sockets. Then I discovered the insulation had faded and the mystery was solved. 🙂

Relays, Sockets and Wiring Notes From Disassembly

Each relay can plug in only one way into the socket. I put each relay loosely into it’s socket, turn it upside down and then remove the relays with the pins and numbers pointing up. This provides a good way to make sure I get the correct terminal plugged into the correct bay of each socket.

I start with the starter relay and plug the double red wire terminal into bay 87, then the double green-blue wire into bay 86 and the blue-yellow wire into bay 85.

Using Relay Terminal Numbers to Install Wires In Bottom of Relay Socket Correctly

Using Relay Terminal Numbers to Install Wires In Bottom of Relay Socket Correctly

Using Relay Terminal Numbers to Install Wires In Bottom of Relay Socket Correctly

Now I plug wires into the horn relay starting with the two red wires into bay 30 and the two brown wires into bay 85 and the brown-white into bay 86. The two black wires go the each horn and plugs into bay 87.

Starter Relay (Left) and Horn Relay (Right) Wire Detail

Starter Relay (Left) and Horn Relay (Right) Wire Detail

Starter Relay (Left) and Horn Relay (Right) Wire Detail

Here is where the wires from the main harness go into each socket; the starter relay socket is on the left and the horn relay socket is on the right.

Wiring to Starter Relay (Left) and Horn Relay (Right) Sockets

Here is the assembly ready to thread into the frame. The blue wire with the white plastic connector plugs into a companion blue wire from the alternator harness.

Horn Wires From Horn Relay

Install Main Wire Harness in Frame

I did not remove the main wiring harness connections from the headlight shell other than one by one to verify that the contacts were clean and in good condition. So I need to install the headlight shell and then route the harness along the frame spine tube. To do that, I install the top fairing bracket which has the ears the headlight shell mounts to. Unlike the “naked” or “S” model bikes that have headlight ears that fit on the top of the fork tubes between the top brace and lower triple clamp, the RS fairing bracket supports the headlight.

Install Top Fairing Bracket

Powder Coated Upper Fairing Bracket Includes Ears for Mounting Headlight Shell

Powder Coated Upper Fairing Bracket Includes Ears for Mounting Headlight Shell

There are two bolts that thread into two tapped holes in the steering stem that secure the upper fairing bracket to the frame.

Upper Fairing Bracket Mounting Bolts

Upper Fairing Bracket Mounting Bolts

Tapped Holes in Steering Stem for Mounting Upper Fairing Bracket

Tapped Holes in Steering Head for Mounting Upper Fairing Bracket

Upper Fairing Bracket Mounted to Steering Head

Upper Fairing Bracket Mounted to Steering Head

Install Headlight Shell

The ignition switch for the RS is in the dash instead of in the left side of the headlight shell as is the case for naked and “S” bikes. Consequently, a threaded plug is installed in the left side of the headlight shell to take the place of the ignition switch and its threads.

Headlight Shell Left Side Plug That Replaces Ignition Switch

Headlight Shell Left Side Plug That Replaces Ignition Switch

A rubber gasket and metal washer go on the plug so they fit against the inside of the headlight ear of the upper fairing bracket.

Headlight Shell Left Side Hardware Detail

Headlight Shell Left Side Hardware Detail

The right side of the headlight ear has a large metal plate that is tapped for a mounting bolt.

Headlight Shell Right Side Detail

Headlight Shell Right Side Detail

Another rubber gasket goes between it and the upper fairing bracket ear.

Location of Headlight Shell Right Side Rubber Washer

Location of Headlight Shell Right Side Rubber Washer

I install the headlight shell by inserting the left plug into the ear of the upper fairing bracket and carefully pulling the right ear outward until the right side of the headlight shell slips inside the ear being careful not to scratch the ear nor the headlight shell and keeping the rubber gasket between the ear and the metal plate.

Headlight Shell Inserted Inside Right Mounting Ear with Rubber Gasket Between Ear and Shell

Headlight Shell Inserted Inside Right Mounting Ear with Rubber Gasket Between Ear and Shell

Here is the hardware that goes on the outside of the right side ear.

Headlight Shell Right Ear Hardware Sequence

Headlight Shell Right Ear Hardware Sequence

Headlight Shell Right Ear Hardware Detail

Headlight Shell Right Ear Hardware Detail

I leave the bolt loose until I get the left side hardware installed. It includes another rubber gasket that fits against the outside of the left ear and two metal washers and a chrome nut. One washer is flat and goes against the rubber gasket and the second is wavy and goes against the chrome nut.

Left Headlight Shell Ear Hardware Sequence

Left Headlight Shell Ear Hardware Sequence

Left Headlight Shell Ear Hardware Detail-Rubber Gasket

Left Headlight Shell Ear Hardware Detail-Rubber Gasket

Left Headlight Shell Ear Hardware Detail

Left Headlight Shell Ear Hardware Detail-Flat Washer

Left Headlight Shell Mounting Hardware On Outside of Ear

Left Headlight Shell Ear Hardware Detail-Wave Washer and Chrome Nut

I snug up the right bolt and left chrome nut with the headlight approximately centered in the two ears. I’ll adjust the left-to-right and up and down angle of the headlight to align the headlight later.

Here is the headlight shell mounted in the ears of the upper fairing bracket with the left and right handlebar switches showing.

Headlight Bucket Installed with Handlebar Switches and Ignition Terminals Showing

Headlight Bucket Installed with Handlebar Switches and Ignition Terminals Showing

I route the main harness and the various branches starting from the front of the bike.

Left Handle Bar Clutch Switch Plug

This is the branch that connects to the left handlebar clutch switch.

Clutch Switch Plug Plugs into Left Handlebar Sub-harness Plug

Clutch Switch Plug Plugs into Left Handlebar Sub-harness Plug

Front Brake Master Cylinder Wires

I route the branches that go to the front brake master cylinder and connect them. There are two wires that go to the fluid reservoir level switch in the cap and the two wires that go to the front brake light switch on the front of the master cylinder.

Wires to Brake Fluid Reservoir Low Level Switch in Fill Cap

Wires to Brake Fluid Reservoir Low Level Switch in Fill Cap

Wires To Front Brake Light Switch

Wires To Front Brake Light Switch

I previously installed all the main harness wires into the horn and stater relay plugs and push that through the gap between the frame front down tubes.

Horn and Stater Relay Sockets Pushed Through the Two Front Down Tubes

Horn and Stater Relay Sockets Pushed Through the Two Front Down Tubes

Install Horn and Starter Relays

I add the missing wires to the relay sockets that come from the (+) battery cable and the alternator.

Battery (+) Cable Wire for Stater Relay (I added Red Paint)

Starter Relay Wire Detail

Then I install the two wires that come from the diode board and starter solenoid via the wire harness sticking out of the top of the engine behind the front engine cover.

Alternator Blue Wire

The black wire comes from the starter solenoid and goes to terminal 30 on the starter relay.

 Black Wire From Starter Solenoid Connects to Terminal 30 on Starter Relay

Black Wire From Starter Solenoid Connects to Terminal 30 on Starter Relay

The blue wire comes from the diode board and connects to the main harness blue wire via the white plastic plug.

Blue Wire from Alternator

Blue Wire from Alternator

Blue Wires Connected

Blue Wires Connected

Install Voltage Regulator

I bought an EME electronic voltage regulator and install it where the original regulator went. It mounts to the tab on the right side of the spine tube with two Allan bolts. The three prong plug from the alternator wiring harness plugs into the bottom. There is a small white dial on the bottom that adjusts the maximum charging voltage, but I leave it at it’s original setting.

EME Electronic Voltage Regulator and Mounting Bolts

EME Electronic Voltage Regulator and Mounting Bolts

EME Voltage Regulator-Bottom (White Dial Sets Regulator Voltage)

EME Voltage Regulator-Bottom (White Dial Sets Regulator Voltage)

EME Electronic Voltage Regulator Fits Triangular Plug

EME Electronic Voltage Regulator Fits Triangular Plug

Triangular Plug Inserted in EME Electronic Voltage Regulator

Triangular Plug Inserted in EME Electronic Voltage Regulator

Install Dyna III Electronic Ignition Module

The bike had a Dyna III electronic ignition with the “brown” dual plug coils. Due to the corrosion inside the points housing and damage to the aluminum sleeve that has the magnets for the hall effect sensor that acts as the points, I replaced it Dyan III ignition system with a new one. The dual plug coils did not appear to be damaged so I will use them.

You can read about how I installed the points and adjusted the advance to compensate for the dual plug heads here:

I repainted the coil brackets and then installed them and the coils on the frame. Note the brackets have a bend in them and I show the correct orientation of the bracket on the frame and how the coils bolt to the bracket.

Painted Coil Bracket

Painted Coil Bracket

Orientation of Dyna III Right Side Coil Bracket When Mounted

Orientation of Dyna III Right Side Coil Bracket When Mounted

Orientation of Dyna III Right Side Coil Bracket

Orientation of Dyna III Right Side Coil Bracket

Orientation of Dyna III Right Side Coil on Bracket

Orientation of Dyna III Right Side Coil on Bracket

I removed the spade terminals from the coils to clean them. Note that the clearance between the bracket bolt and the spade terminal bolt is so limited that the spade terminal bolt has to be installed first and then the bracket bolt inserted just enough to thread the nut on the end and then holding the bracket bolt nut while the head of the bolt is tightened.

Dyna III Coil Bracket Bolt Obstructs Spade Terminal Mounting Bolt

Dyna III Coil Bracket Bolt Obstructs Spade Terminal Mounting Bolt

Attaching Dyna III Coil Bracket Bolt After Terminal Attached

Attaching Dyna III Coil Bracket Bolt After Terminal Attached

Dyna III Coil Bracket Bolt and Terminal Screw-Very Little Clearance

Dyna III Coil Bracket Bolt and Terminal Screw-Very Little Clearance

The other bracket bolt is easy to install.

Orientation Of Dyna III Coil Bracket and Bracket Bolt

Orientation Of Dyna III Coil Bracket and Bracket Bolt

I clean the paint off the coil bracket around the holes the Allan head bolts go through to mount the brackets. I will attach ground wires to the bolts and want to get a solid ground.

Scrape Paint Around Bolt Hole on Coil Bracket

Paint Removed Around Bolt Hole on Coil Bracket

I attach the spade terminal with several brown ground wires to the left front bolt and use my ohm meter to test for a solid ground.

Testing Ground Connection is Good

Testing Ground Connection is Good

The coils are connected in series with a short, black jumper wire that goes between the two inner spade terminals on the coils.

Dyna III Coils Showing Black Jumper Wire Connection

Dyna III Coils Showing Black Jumper Wire Connection

Short Black Jumper Wire Between Inner Spade Terminals of Coils

Short Black Jumper Wire Between Inner Spade Terminals of Coils

The amplifier has two sets of wires: a white and red pair that plug into the leads coming from the points and a brown, red and black set that go to the coils. The red that goes to the points has a micro plug and can’t be confused with the red that goes to the coils which has a female spade terminal.

New Dyna III Control Unit with Mounting Hose Clamp (I Didn't Use it)

New Dyna III Control Unit with Mounting Hose Clamp (I Didn’t Use it)

The left coil outside terminal has the red wire from the Dyna III control unit and the green-blue wire from the main wiring harness attached to it.

Red Dyna III Control Unit Wire Attached to Left Coil

Red Dyna III Control Unit Wire Attached to Left Coil

Left Coil Connections and Ground Wires Attached Under Coil Bracket Bolt

Left Coil Connections and Ground Wires Attached Under Coil Bracket Bolt

 

The right coil outside terminal has the brown Dyan III wire from the control unit attached.

Dyna III Control Unit Brown Wire On Right Coil Spade

WARNING:
The black wire that goes to the condenser inside the front engine cover is NOT connected to the coils when using the Dyna III electronic ignition. If it is connected, the bike will not start.

The black ground wire from the Dyna III control unit attaches to the right front Allen bolt for the coil bracket. Again, I check that wire for a solid ground using my ohm meter.

Dyna III Ground Attached to Right Coil Bracket Bolt

Dyna III Ground Attached to Right Coil Bracket Bolt

I coil the extra wires in two bundles secured with a shrink tubing; one with the leads from the Dyna III control unit and the other with the two leads that go to the points. I zip tie the two bundles together and tuck that into the space between the spine tube and the reinforcing tube.

Dyna III Wires Neatly Bundled

Dyna III Wires Neatly Bundled

I install an EME electronic voltage regulator that is not as tall as the original voltage regulator can. There is enough room to mount the Dyna III control unit on top of it. I use Velcro to attach it to the top of the EME regulator. This space gets some air flow from the front so both units should stay cool.

Dyna III Control Unit Velcroed to Top of EME Voltage Regulator

Dyna III Control Unit Velcroed to Top of EME Voltage Regulator

Install Rear Brake Switch

The switch mounts on a tab inside the right rear muffler bracket with two screws. The main wiring harness has a branch with two wires, green-black and green-red, that go the the terminals of the switch. I route this branch under the batter box and secure with a couple of tie wrapes. There is a black rubber cover that fits over the top of the switch to protect the terminals from water and crud.

Rear Brake Light Switch and Mounting Screws

Rear Brake Light Switch and Mounting Screws

Rear Brake Light Switch Bracket on Inside of Right Rear Muffler Bracket

Rear Brake Light Switch Bracket on Inside of Right Rear Muffler Bracket

Rear Brake Light Switch Orientation on Bracket with Rod Through Hole in Bracket

Rear Brake Light Switch Orientation on Bracket with Rod Through Hole in Bracket

Rear Brake Light Switch Mounts with Two Screws on Tab

Rear Brake Light Switch Mounts with Two Screws on Tab

Rear Brake Switch Rubber Cover Has Holes for Wires

Rear Brake Switch Rubber Cover Has Holes for Wires

Threading Wires Through Rear Brake Switch Rubber Cover

Threading Wires Through Rear Brake Switch Rubber Cover

Wires Route Through Holes in Rubber Cover

Wires Route Through Holes in Rubber Cover

Rear Brake Switch Installed Showing Wires Attached to Switch Terminals

Rear Brake Switch Installed Showing Wires Attached to Switch Terminals

Rear Brake Switch Installed

Rear Brake Switch Installed with Black Rubber Cover on Top

Install New Oil Pressure Switch

The bike came with a VDO oil pressure gauge and sender. I decided to install the original oil pressure switch instead of the gauge.

The wire for the switch is in the same branch of the main harness that includes the transmission neutral switch.

To prevent potential leaks from the seal between the case and plastic center of the switch, I put some green loctite which wicks into any gaps between them.

Green "Wicking" Loctite Applied Around Edge of Phenolic And Metal Case

Green “Wicking” Loctite Applied Around Edge of Phenolic And Metal Case

The wire terminal was changed to a ring terminal. I remove it and crimp and solder a female spade terminal with some shrink tubing to seal the wire to the spade.

Oil Pressure Wire with Shrink Tube

Oil Pressure Wire with Shrink Tube

New Female Spade Terminal

New Female Spade Terminal

Crimping Anvils

Crimping Anvils

Oil Pressure Spade Located on Wire

Oil Pressure Spade Located on Wire

Oil Pressure Spade Crimped to Wire

Oil Pressure Spade Crimped to Wire

I like to add some flux when I solder even though the solder has rosen flux in the center.

Flux Paste

Flux Paste

Flux Melted on New Oil Pressure Spade

Flux Melted on New Oil Pressure Spade

Solder on New Oil Pressure Spade

Solder on New Oil Pressure Spade

I use two pieces of shrink tubing, a smaller diameter one around the spade and then a larger diameter one around it and the wire.

Shrink Tube Over New Oil Pressure Spade

Shrink Tube Over New Oil Pressure Spade

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

Shrink Tube Over Oil Pressure Spade Terminal

I install the oil pressure switch into the block with a sealing washer. I don’t over tighten it as that can crack the metal-to-plastic seal and let it leak.

Oil Pressure Switch Installed

Oil Pressure Switch Installed

Oil Pressure Switch Connected

Oil Pressure Switch Connected

Install Rear Wire Sub-harness

I removed the plug from the rear wiring sub-harness so I can clean the terminals. That allows me to thread the rear harness through holes in the sub-frame starting from the hole in the rear with the plug terminals going in first.

Preparing Rear Sub-harness for Pulling

Preparing Rear Sub-harness for Pulling

I wrap masking tape around the terminal ends and twist it around the end of a piece of electrical wire I threaded from the front hole and wrap another piece of masking tape around the joint.

Preparing Rear Sub-harness for Pulling

Preparing Rear Sub-harness for Pulling

Ready to Pull Rear Sub-harness Through Sub-frame

Ready to Pull Rear Sub-harness Through Sub-frame

When I pull the plug terminals through the front sub-frame hole, I remove the tape so I can put the terminals into the plug.

Rear Sub-harness Wires Pulled Through Sub-frame

Rear Sub-harness Wires Pulled Through Sub-frame

I use the wiring diagram I made when I removed the terminals from the rear plug and also verify the wire colors match up with the ones in the other half of the plug attached to the main wiring harness.

Rear Harness Terminal Block Pin Diagram

Rear Harness Terminal Block Pin Diagram

When I install the rear fender, I attach the rear brake light housing, rear turn signal stalk and turn signals and attach the wires inside the brake light housing.

Main Harness and Sub-harness Routing

I shot a video showing how I route the main wiring harness and the sub-harness’.

 

2 thoughts on “61 BMW 1977 R100RS Refurbish and Install Wiring & Electrical Components

  1. Hi Brook,
    Mac Morgan here… again.
    I am continuing to enjoy your RS build/rebuild articles. Having owned one since July ’77, I’ve had a few reasons to replace, fix or change things over time. Right now it’s resting in the garage on a batterytender with a tank full of avgas. I know Cutter (he lives up the road from me in NJ and is friends with friends) doesn’t approve of the avgas issue but believe me that over the years it’s saved the interior of the tank and kept the carburetors from constant rebuilding… and the engine loved it! It is formulated for air cooled engines.
    My only suggestion would be to invest in a good pair of crimpers. I probably have 3-4 pair, the best by HERO which came with a Honda sourced electrical connector kit bought years ago. The crimper does a factory job of folding the tabs over the bare wires and then over the insulation. Just a suggestion.
    Keep up the great articles.
    Regards,
    Mac Morgan
    Hockessin Delaware

    • Hi Mac,

      Yeap, a “good” pair is on my “future tool purchases wish list”. I thought the ones I picked up at NAPA would work, but they did not neatly fold the tabs over on the wire as I expected.

      Best.
      Brook.

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