Note: I'm writing part of this, especially the last half, before actually doing it on this bike so I may change things as I go. I don't need a document to do this so the only way I can be sure the document is right is to write it and then do it! Also, I will add pictures but that will come a bit later. Finally, this is not finished but I've spent over 20 hours on it and will finish it!
This document tries to cover wiring a stock Norton Commando, a stock Norton Commando with the Colorado Norton Works (cNw) e-start, and the Norton Commando 850 MK3 using my methods. I will try to explain where there are differences in them. The Commandos with ammeters are not covered but you can call me if you need help with them. Mostly this will work for them as well, but the main battery negative wiring and the location of the master switch and the master switch type are radically different.
Tri-Spark VR-0030 MOSFET Voltage Regulator. Depending on the air filter, the regulator can be mounted in various locations so the instructions will be somewhat vague on its wiring.
Tri-Spark Tri-0006 ignition system.
No connector block under the tank - most connections in the headlight shell.
No bullets - WAGO connectors instead.
Positive Ground
Correct wire colors
Correct wire but see the next section that explains what that is.
Throughout this document:
You will see the term "breakout". This means where a wire (or wires) leaves the main harness and goes somewhere.
You will see references to "Combat5". It is a 1972 Combat with the cNw electric starter and air filter. It is being wired and documented here, see: Fifth Customer Combat - GME. I either use its pictures or refer you to a date or date range in that page often.
The MK3 is quite a bit different than all others in that there is a console with warning lights and the master key. I mention the differences but until I wire the next bike I'll build (it's an MK3), I can't be very specific here. However, while not overly specific, this is how I wire a MK3: Custom Wiring a 1975 Norton Commando for Reliability - GME. For now, it's better to at least refer there for the MK3 info.
Things you Need
Correct Wire
Originally, most British bikes were wired with all "14 strand" wire. That literally means flexible multi-strand wire with 14 individual copper strands; it was a British standard. It is equivalent to AWG 18 gauge, and it is able to carry 8 amps.
I buy my wire from: https://www.britishwiring.com/default.asp. They have several wire types. The PVC wire is nearly identical to the original. They have all the correct colors.
One pitfall with the original wiring is that the ground and Brown/Blue from the battery to the Master Switch were 14-strand. That meant that the wires were nearly fully loaded with the lights on and the engine running. Turn on the turn signals and push the horn button and more than 8 amps was flowing through them - not good!
I use 28-strand for the main ground wire and for the Brown/Blue wire. Also, I use three 14-strand white wires from the master switch. White wires are the "hot" wires. I use one for the left handlebar console, one for the right, and one for the other things that need -12 volts.
I do all this so there is never an overloaded wire anywhere in the bike.
The 28-strand wire is equivalent to 14 gauge AWG.
Because I happen to have a 100' spool of 14 gauge red wire and a 100' spool of 18 gauge red wire, I use that instead of the 28-strand and 18-strand red wires, but you can't tell the difference looking at them.
Zip Ties
I use LOTS of 4" zip ties - buy a bunch at once so you are not nickel and diming yourself! On Amazon the 1000 pack of 4" costs about $8 which is less than a penny each. If you are wiring one bike, then buy at least 200 or if you're really cheap, live with 100. On Amazon a 100 pack costs $2 less than the 1000 pack I buy but then the ties are 6 cents each!
Sleeving
I use sleeving on all wires outside the main harness and on the wires to the taillight. I have every size that Amazon sells of PVC sleeving but you do not need all sizes. Just make sure to get the "uxcell Black PVC Tube Wire Harness Tubing". As of this writing, all sizes are available here: https://a.co/d/03Dxl8Um. You need:
3mm Good for a single 14-strand or 28-strand wire
4mm It is possible to put two 14-strand wires through but difficult. Fine for one 28-strand but I prefer 3mm for that.
5mm Easy to put two 14-strand wires through. Fine for one 28-strand but I prefer 3mm for that. Would work for two 28-strand but that is not needed in my system.
8mm Good for four 14-strand and one 28-strand. Use this for the wires to the taillight.
12mm, 14mm, or 16mm You need about 14-15" for the harness where it goes around the steering head. 12mm will just barely work, 14mm is optimal and 16mm will work fine.
You could use heat shrink tubing instead of sleeving, but I don't recommend it. The sleeving is flexible, UV safe, gloss black, tough and made for harnesses.
Harness Wrap
This looks like electrical tape but has no adhesive and it is meant for wrapping automotive harnesses. I prefer this one from British Wiring: "Harness Tape, 3/4" Wide - Black (C453)" but the similar ones that Amazon sells are fine too. I find the 1" wide version harder to wrap nicely so I stick with the 3/4" wide. NEVER use electrical tape - it makes a gooey mess over time!
Test Leads
These are not absolutely required but I find them handy. I use these: https://a.co/d/0dwG4yPQ
WAGO Connectors
WAGO is a German company that makes lever lock connectors. They work for all wire sizes used here and many more. They cost less than bullets and in most cases that much less space. They have four types. I'll count how many I use and list it here later - the numbers listed are from memory.
Part
Description
Needed
WAGO 221-412
Two Connection Lever Lock
~15
WAGO 221-413
Three Connection Lever Lock
~5
WAGO 221-415
Five Connection Lever Lock
~5
WAGO 221-2401
Inline Two Connection Lever Lock
4-5
You can use standard bullets - British Wiring has all you need. However, they are expensive, a PITA, and I no longer use them.
Amazon has several kits of WAGO connectors plus individual connectors. I buy them in large quantities so I can probably save you a little money if you get them form me.
Meter
You need a voltmeter and an ohmmeter (multimeter has both). I DO NOT like digital for any sort of automotive work! An inexpensive analog meter is much better. In fact, my favorite meter came from Radio Shack years ago for $3.00. The voltmeter needs a range for reading battery voltage - 15 volts DC is good but many have 2.5, 5, 10, and 50 and more. The 50 range will work fine it's just harder to get a exact reading. The Ohmmeter portion must have a x1 range and it's nice if it makes a noise when connected. Checking today, the best option I see on Amazon is: https://a.co/d/00ZoVWox. If you already have a digital meter, it's fine for static wiring testing like you'll do here, they just are not good for running bikes - too much electrical noise.
Getting Started
General Information
To start you need several wires from the headlight shell to the taillight area. Unless otherwise noted, all wires in this document are 14-strand PVC coated.
Cut but don't run yet one Red 28-strand wire
Cut but don't run yet one Brown wire
Cut but don't run yet one Brown/Green wire
If you will be using turn signals:
Cut but don't run yet one Green/White wire
Cut but don't run yet one Green/Red wire
These are all 81" long. Yes, throughout, all wires are longer than they need to be, but there is nothing worse than doing the final wiring and having one or more wires too short!
The red wire will have several red wires spliced to it. For most other wires you can choose to splice or connect in the headlight shell. Generally, I splice. Where I splice, I tell you how to not splice except for the red wires and the Brown/Blue wires. If you don't want to splice these, you're on your own.
Building the Main Ground Wire
All measurements in this section are measured from the end of the red wire in the taillight area.
The back of the rear frame grommet will be at 31". I put three crisscrossed zip ties there to stop confusion later.
These splices must be done and insulated in order! When I splice, I strip the loose wire a bit longer than the part of the main wire I strip. I use an X-Acto knife to strip the main wire. I then tightly wrap the wires together with clean hands and then solder with rosin core solder - it is imperative that you not use acid core (plumbers) solder! Although it is not needed, I clean the splice after soldering with denatured alcohol to remove any rosin. I then use a piece of heat shrink slightly longer than the splice, shrink it, and then follow with one about 1-1/4" long centered over the splice. Double heat shrink is the kind of overkill that costs very little and greatly improves the chance of long-term success.
Splice a 27" 14-strand red wire to the main red wire centered at 40.5". This will be the horn ground. This wire exits the splice to the rear.
NOTE: this length and location are for the horns I use mounted where I mount them. If you use the original location or a different location or horn type, you must figure it out! Later, I'll add a picture of my horn mounting.
Splice a 27" 28-strand red wire to the main red wire centered at 42-1/4". This will be the battery + wire. This wire exits the splice to the rear.
There will be a bundle of wires that exit the harness header that go to the master switch. Nominally the center of the breakout to the master switch is at 45-3/4" from the taillight red wire. You'll have to decide the exact location for yourself, but it should be somewhere between 45" and 46-1/2". Just don't interfere with the front frame grommet and be sure it can route nicely to the Master Switch. The MK1A, MK2A, and MK3 require particular attention if using the plastic air box. If using the cNw air cleaner, no telling where or how you will decide to mount the Master Switch and if using the "Hamcan" you might have the regulator mounted to the back of it so again this routing has to be up to you and well thought out! I put 4 zip ties there, side by side, and a sharpie mark on each side of the four on the main red wire as a reminder where that will be. The location of that breakout is one thing that must be right; most other things can vary some. You can look at June 6, 2026 through June 7, 2026 to see where the master switch got mounted on "Combat 5" which is a 1972 Combat getting a cNw e-start: Fifth Customer Combat - GME
Splice an 11" 28-strand red wire to the main wire centered at 53-1/2". This will be the head ground. It is not actually needed for an MK3 or a bike with the cNw e-start, but I use it anyway. The wire exits the splice to the front. BTW, officially the wire connects to one of the studs through the head steady - don't do that. Still use a ring connector and put it under the timing side Allen screw that connects the head steady to the head. If you use one of the aftermarket fancy head steadies (I never do), you'll have to figure that out for yourself. The point is to have a solid engine ground since the Commando engine is rubber mounted.
Splice a 14" 14-strand red wire to the main wire centered at 59-1/2". This will be the coil ground. This wire exits the splice to the front.
Building the Brown/Blue Wire.
This wire connects connection 1 of the Master Switch to the minus of the battery via the fuse. I use the standard fuse holder, and it takes a bit of skill and patience to clamp and solder the connectors on the wire.
I don't install the fuse holder until I'm positive where I want it and the wiring is in place; the wiring does not need to be finished, it just needs the location locked down and the battery sitting where it will go. Note that the plus and minus of the battery can be on either side depending on what battery you bought. Also, the size of the battery varies. I use 9ah AGM (e.g., YB9A-A or YB9A-B) batteries if not electric start and Shorai LFX 18A1-BS12 for electric start bikes and they are MUCH smaller than the AGM batteries.
Cut a length of Brown/Blue 28-strand wire 41" long and mark one end of it. Note: the MK3 will be different! Also, if the Master Switch is very far from the normal location, this wire might need to be longer at the Master Switch end.
Cut a length of Brown/Blue 28-strand wire 7" long.
Splice the short Brown/Blue wire to the long one with the splice centered 17" from the marked end of the long wire. The short wire exits the splice to the rear from the marked end of the long wire. The free end of the short wire will eventually connect to the black wire for the Tri-Spark regulator. If the regulator will be mounted in front of the splice, then the wire needs to leave the splice toward the other end so figure out the regulator mounting before making this wire. Some people use the Andover Norton PODtronics mount (13.1667 or 13.1667/B) and some mount to one of the Z-plates so be sure the short wire is long enough - it should be in all these scenarios as the regulator's red and black wires are long - but check - PITA to fix later.
Zip tie the Brown/Blue and Red wires together using the Master Switch breakout you marked on the red wires. Just make it snug and put another zip tie further back to keep the Brown/Blue in place.
Master Switch Wires
I don't know your master switch location, so you'll have to think this through. If you happen to be working on a 1972 Combat with the cNw starter, cNw air filter and my Master Switch Bracket installed like I have on Combat5 then these instructions are correct. If wiring a MK3 the Master Switch is in the black console so the wire from the battery negative goes to the headlight shell - see the MK3 wiring page I mentioned in the introduction.
The White Wires
Cut three White wires that reach from the Master Switch to the headlight shell. Make sure the headlight end has at least 4" past the front of the shell and that the Master Switch end is through the bracket at least 2" past the end of the bracket with the wires routed along the frame nicely. Now, mark each wire:
One with one mark on both ends. This will be for the left-hand handlebar console.
One with two marks on both ends. This will be for the right-hand handlebar console.
One with three marks on both ends. This will be for the things that are not part of the handlebar console circuits (brake light, flasher).
When you actually wire the Master Switch, the first two wires will be in one spade connector and the other will be in a second spade connector.
Building the Brown and Three-Mark White Wires.
The Brown wire is for the brake light, and the one you've cut goes from the headlight shell to the taillight. On Combat5, I used the mixed option. Options:
Spliced
Run a White wire leaving excess from the rear brake switch along the Brown wire to some point of your choosing through the rear grommet to some location between the front grommet and head steady rubbers. Splice this wire to the White wire between the Master Switch and headlight shell. I used a 57" wire spliced to the White wire with three marks with the splice centered at 19" from the Master Switch end of the wire. The splice exits to the rear.
If you put the flasher on the back of the frame cross member as is standard for pre-MK3, run a White wire leaving excess from the flasher along the White wire to the rear brake switch. It can be spliced to that wire as long as it goes forward of the rear grommet and can be forward of the front grommet. Splice this wire to the White wire between the Master Switch and headlight shell or rear brake White wire.
Non-Spliced:
Run a Brown wire leaving excess from the rear brake switch to the headlight shell.
Run a White wire leaving excess from the rear brake switch along the Brown wire to the headlight shell.
If you put the flasher on the back of the frame cross member as is standard for pre-MK3, run a White wire leaving excess from the flasher along the White wire to the headlight shell.
Mixed:
Run a White wire leaving excess from the rear brake switch along the Brown wire to some point of your choosing through the rear grommet to some location between the front grommet and head steady rubbers. Splice this wire to the White wire between the Master Switch and headlight shell. I used a 57" wire spliced to the White wire with three marks with the splice centered at 19" from the Master Switch end of the wire. The splice exits to the rear.
If you put the flasher on the back of the frame cross member as is standard for pre-MK3, run an 18" White wire from the flasher area along the White wire to the rear brake switch to the headlight shell. Splice this wire centered at 45" from the end of the White wire to the rear brake switch.
Run a Brown wire leaving excess from the rear brake switch to the headlight shell.
I put the Brown and White wires to the rear brake switch in a 36" piece of sleeving. There are starting to be a lot of loose wires and the sleeving makes it clear where they are going.
I generally splice the White wires and not the Brown. The Brown already must have a WAGO connector in the headlight shell to connect the front brake switch, so using a 3-connection WAGO takes very little more space than a 2-connector WAGO connector. The White wires cause adding a 5-connector WAGO that otherwise is not needed in the headlight shell and adds three connections - I try my best to minimize connections!
Building the Brown/Green Wire.
The Brown/Green wire is for the lighting and especially the taillight. It goes from the taillight to the headlight shell and also to the Master Switch. Options:
Spliced: Run a Brown/Green wire from the Master Switch through the front frame grommet and splice to the Brown/Green wire from the taillight to the headlight. On Combat5, this wire is 20" long and the splice is centered at 49" from the end of the taillight wires. This wire exits the splice to the rear.
Non-Spliced: Run a Brown/Green wire from the Master Switch through the front frame grommet to the headlight shell. Later the two Brown/Green wires run so far will be connected with the other Brown/Green wires in the headlight shell.
I generally splice the White and Brown/Green wires and not the Brown. The Brown already must have a WAGO connector in the headlight shell to connect the front brake switch, so using a 3-connection WAGO takes very little more space than a 2-connector WAGO connector. There are a bunch of Brown/Green wires to connect in the headlight shell, so splicing reduces them by one. The White wires cause adding a 3-connector WAGO that otherwise is not needed in the headlight shell and adds three connections - I try my best to minimize connections!
Running the Wires
The Main Wires
Route the:
Made-up Red and Brown/Blue wires through the front and rear grommets.
The made-up Brown, Brown/Green, and third White wires.
The other two or four wires you cut before (Brown, Brown/Green, Green/White, and Green/Red).
The two White wires with one and two marks.
Match up the ends of the wires at the taillight and put a zip tie on them and put a couple more forward of that so the wires are nicely run together. Then attach them to the frame along the timing side. I use a roll of Velcro cut to lengths I need for this. Also run the spliced, non-spliced, or mixed White and Brown wires you made up.
This is the time to make very sure you are happy with the location of all wires so make sure they are routed and secured completely together and to the frame, but not secured permanently.
It is also the time to figure out where the various wires in the battery area will break out from the main harness. I put two zip ties at each of these locations so I can keep track of them. Once all wires are run you will have to remove the entire harness and add sleeving (preferred) or heat shrink to certain areas and then wrap the harness, so you need to know where the breakouts are!
As you add wires, zip tie them to the routed main harness and make sure you use enough zip ties so you're not confused when you take the harness off the frame for the next steps. Also make sure the harness is routed nicely as you install zip ties and they will cause the harness to somewhat hold a shape.
The Rest of the Harness Wires
I mostly don't give lengths in this section. Just make sure the headlight shell ends match up with the wires already run and tie each wire to the main harness as it runs. I usually cut the old zip ties and add new when running each wire.
If using the Don Pender oil pressure switch, it mounts to the rocker feed line at the bottom of the timing cover. A White/Brown wire is needed for it to the headlight shell. Where it is outside the main harness, I put it in a piece of 3mm sleeving, and it breaks out of the harness about 1" before the front of the front frame grommet. The sleeved wire then goes through the front frame grommet and follows the timing side frame tube down to the switch.
Run a Light Green/Brown wire from the headlight shell to the end of the White wire to the flasher as mentioned before.
Run a Purple/Black wire from the headlight shell to the end of the 14-strand Red wire mentioned earlier for the horns and pay attention to the comments made there!
Run a Blue/Yellow wire from the Master Switch to the headlight shell. This wire will connect to the switch in the headlight shell. It will be connected to terminal four of the master switch.
Run a White/Yellow wire from the headlight shell to about 3" in front of the rubber mounts of the head steady. Run this even if you don't plan to use the kill button - I'll explain later hat to do in that case.
If wiring a MK3 you need a White/Red wire from the headlight shell to the starter solenoid. If wiring a cNw electric starter, you must decide whether to follow their instructions and route their long wire. I don't do that. I run a White/Red wire from the headlight shell to near the flasher and I connect their starter wire to that.
Zip tie all the wires together. I go along cutting zip ties that are on less than all of the wires and adding new around all wires.
The Tri-Spark ignition needs two wires - a Black/White and a Black/Yellow.
These don't have to be prepared right now, but I put them here so the coil and White/Yellow wiring will make sense.
If you have two coils, the Red 14-strand wire from the harness will connect to the plus on one coil and there must be a jumper from the minus of that coil to the plus of the other coil. If you have a single coil, the Red 14-strand wire from the harness still connects to the plus (if marked) on the coil.
I put the Black/White and Black/Yellow wires in 4mm sleeving (with difficulty) or 5mm sleeving.
The Black/White wire connects to the minus of the coil where there is no wire.
The Black/Yellow connects to the White/Yellow from the headlight shell. This White/Yellow is the "hot" side of the kill button and provides the power to the Tri-Spark unit.
Note: if you don't want to use the kill button still run the White/Yellow but in the headlight shell, connect it to the White wire with three marks instead of the White/Yellow from the handlebar console.
Before moving on, look at the wiring diagram and at each thing that must be connected to be sure there is a wire to connect!
Preparing, Connecting, and Testing the Taillight
The taillight and turn signals (if used) need a good ground. The fender is not a good ground! That's the reason there is a Red ground wire to the taillight in my wiring.
The taillight is not ready to be permanently mounted yet - these tests are to ensure once you have wrapped the harness that the taillight will work. Once the harness is wrapped and the harness is in place on the bike, I recommend doing these tests again before doing the rest of the connections throughout the bike.
Lucas 679 (1971-1972) Commandos:
Has no red wire and is expected to get its ground from the fender - that's fine on Triumph and BSA, does not work on Commandos.
The turn signals are expected to get their ground from the fender via the mounting bracket. That won't work either and if that bracket is powder coated there is no chance!
See Combat 5, June 6, 2026 to see how I prepare the taillight.
Once prepared, all red wires connect together.
Do it my way and you never have grounding problems in the taillight area; don't and you likely will!
This taillight is very hard to wire on a Commando as the taillight fairing is a major part of the mounting. On the later taillight everything is mounted and wired before the fairing goes on.
Lucas 917 (1973 and later)
The taillight itself has a red wire but the turn signals do not.
Put all five wires through a length of 8mm sleeving that extends from about 3" in front of the rear frame grommet back to the taillight at a point where the wires are all protected from rubbing on things.
Since the harness needs to come off the bike one or two more times, the connections below are best done temporarily and not cutting the wires to length yet. You can skip this testing if you are positive you've made no mistakes. I use test leads with "alligator clips" to make the connections and I do the tests now and again once I start the final wiring.
Connecting is easy once the taillight is prepared. All Red wires connect together, and the other wires are a one-for-one connection.
At this point, I test to be sure I have run all the wires, and the splices are right if used. Make sure there are no wires touching ground or together in the headlight area or anywhere.
If you used the spliced version of the Brown and Brown/Green wires:
Connect a 12 volt battery positive to the Red wire in the headlight shell.
Momentarily touch the battery negative terminal to the Brown/Green wire in the headlight shell and make sure the taillight filament of the taillight lights.
Momentarily touch the battery negative terminal to the Brown/Green wire to the Master Switch and make sure the taillight filament of the taillight lights.
Momentarily touch the battery negative terminal to the Brown wire and make sure the brake filament of the taillight lights.
Momentarily touch the battery negative terminal to the Brown wire to the rear brake switch and make sure the brake filament of the taillight lights.
Momentarily touch the negative battery terminal to the Green/White wire and make sure the timing-side turn signal lights. If instead of the drive-side lights, you have the Green/White and Green/Red reversed at the taillight.
Momentarily touch the negative battery terminal to the Green/Red wire and make sure the drive-side turn signal lights.
If you used the non-spliced version of the Brown and Brown/Green wires:
Connect a 12 volt battery positive to the Red wire in the headlight shell.
Momentarily touch the battery negative terminal to each of the Brown/Green wires in the headlight shell from the harness and make sure the taillight filament of the taillight lights.
Momentarily touch the battery negative terminal to each of the Brown wires in the headlight shell from the harness and make sure the brake filament of the taillight lights.
Momentarily touch the negative battery terminal to the Green/White wire and make sure the timing-side turn signal lights. If instead of the drive-side lights, you have the Green/White and Green/Red reversed at the taillight.
Momentarily touch the negative battery terminal to the Green/Red wire and make sure the drive-side turn signal lights.
Preparing to Wrap the Harness
I use sleeving on ALL wires leaving the harness. That sleeving extends past the breakout to near the terminal (if any) that connects to something. At this point as long as a little wire is sticking out from the sleeving where it will connect to something and the harness end is at least 1" into the harness past the breakout point you are fine.
At each breakout, zip tie the sleeved wire exactly where you want it to break out and then one more time near the end of the sleeving.
The hardest breakout to handle is the one to the master switch since the wires are coming from two directions. You must never kink wires. Copper when kinked eventually becomes "work hardened" and brittle - this is not good. A small radius is fine, just not a kink. In this one place, electrical tape can be used to cover the breakout "V" of the wires and the end of the sleeving so the sleeving cannot slip but it must be covered with the harness wrap when you finally wrap the harness.
It is best at this point to wire the Master Switch, Fuse Holder, and Head Ground to allow testing going forward. Just make sure the harness is on the bike exactly where it will be in the end.
Wiring the Master Switch
Mount the Master Switch in the bracket and route the wires exactly where you will have them when done, then:
Look at the wires and rear rubber cover for the master switch. The sleeving must go inside the cover but not too far.
The MK3 rear cover is different from the pre-MK3 in the way that the wires leave the cover. That MK3 cover can be used in certain situations based on where the Master Switch is mounted and on Combat5 it is used for that reason.
Cut the sleeving to the correct length and insert all the wires and the sleeving in the rear cover.
I use a little Vaseline on the sleeving to make this easier.
Slide the cover up the sleeving some to get it out of the way.
Cut all the wires to the correct length to connect to the Master Switch keeping in mind that you are connecting to spade terminals and everything must fit inside the cover!
Check the back of the master switch. If the terminals are not marked, throw it away and buy a proper Lucas Master Switch. The unmarked aftermarket master switches are never good!
As you terminate the wires, you must include a piece of heat shrink that covers the entire spade connector and a small bit of the wire. The wires tend to get pressed together somewhat and you don't want shorts in this!
Terminating and connecting:
The Brown/Blue wire gets a crimped, soldered, and heat shrink cover and gets connected to terminal one of the switch.
The Brown/Green wire gets a crimped, soldered, and heat shrink cover and gets connected to terminal three of the switch.
The Blue/Yellow wire gets a crimped, soldered, and heat shrink cover and gets connected to terminal four of the switch.
This leaves three White wires. Put the one with one mark and the one with two marks in one spade terminal, crimp, solder and cover and connect to one of the two terminals marked two on the switch. Then crimp, solder, and cover the other White wire and connect it to the other terminal marked two on the switch.
Slide the cover down over the wires and while cussing a lot put it over the back of the switch.
Wiring the Fuse Holder and Ground Wire
The Brown/Blue and Red wires for the battery are long enough to reach the terminals of any battery mounted any way. For the MK1A, MK2A, and MK3 the battery is mounted across the frame so the wires must be long enough to take the battery out with the wires connected to be able to disconnect the wires. For the other bikes, the battery is mounted in-line with the bike so the wires don't need to be extra-long and can be disconnected with the battery in place. In either case, the Brown/Blue and Red should be in sleeving past anywhere that they can rub on something.
With the battery mounted and the sleeving installed and zip tied to the main harness where the breakout will be placed, determine the location for the fuse holder and the length of the wire to the negative battery terminal. I like to take the internals out of the fuse holder, put the Brown/Blue completely through it, find where it will be best placed and put a zip tie on the long side. Then take the fuse holder off and cut the wire about 1/4" past the zip tie. Then slide the long end of the fuse holder on the wire from the harness followed by the spring and then crimp and solder the connector on the wire. Yes, it looks impossible to get that big wire in that small connector - it's not - I do it every time! With the piece of Brown/Blue wire you cut off, crimp and solder the other connector then put the wire through the small end of the fuse holder and install a fuse. I use an AGC 5-amp fuse for testing and later switch to the probably fuse once everything is tested.
Now position the fuse holder where you want it and figure out how long to cut the free end of the wire to connect to the battery negative terminal. Then cut the wire there, slide a piece of heat shrink on the wire, terminate the wire with a ring connector that matches the battery screw (crimp and solder) and then slide the heat shrink into place and shrink it.
Now, remove the fuse and connect the Brown/Blue wire to the battery negative. Then route the Red ground wire to the battery and when happy with the routing, cut the wire there, slide a piece of heat shrink on the wire, terminate the wire with a ring connector that matches the battery screw (crimp and solder) and then slide the heat shrink into place and shrink it. Connect the Red to the battery positive.
Figure out the routing and breakout of the Red head wire, put sleeving on the wire as usual between the harness breakout and about 1" from the end of the wire, then terminate the wire with a ring connector that fits the head steady Allen screw. I use a piece of heat shrink enough to cover the ring terminal connection and a little bit of the wire up over the sleeving. Make sure a little of the Red wire is showing between the heat shrink and sleeving so the next person understands that it is a ground. Then temporarily connect the wire to the head.
Testing the Master Switch and Battery Connections
You must be very careful here - make very sure no wires can touch together or the frame or headlight shell. Once sure, make sure the Master Switch is off (looking from the key side all the way counter clockwise is Parking Lights, one click clockwise is Off, another click clockwise is Ignition On and completely clockwise is Everything On.) Like the
earlier testing, the harness still has to come off the bike so I use test jumpers except for the Master Switch. That is fully wired and should stay that way. When ready install the fuse and make sure it doesn't blow. If it does you've made a serious mistake somewhere! If not, do these tests:
Turn the key to Ignition On and using a voltmeter set to DC Volts at 15 volts or the lowest scale you have over 12 volts:
Connect the voltmeter red lead to one of the fins on the head.
Touch each of the three marked White wires in the headlight shell with the Black meter lead and be sure that they have battery voltage (probably around 12.6 volts).
If you used the spliced method for the White, Brown, and Brown/Green wires:
Touch the White wire to the rear brake switch with the Black meter lead and be sure that it has battery voltage.
Touch the White and Brown wires to the rear brake switch together and be sure that the brake light comes on.
Touch the Brown wire in the headlight shell to any of the three marked White wires in the headlight shell and be sure that the brake light comes on.
If you used the non-spliced method for the White, Brown, and Brown/Green wires:
Temporarily connect the White wire from the brake light switch to the White wire with three marks.
Temporarily connect the two Brown/Green wires in the headlight shell together and be sure that the taillight comes on.
Touch the White wire to the rear brake switch with the Black meter lead and be sure that it has battery voltage.
Touch the White and Brown wires to the rear brake switch together and be sure that the brake light comes on.
Turn the master switch to Parking Lights and be sure that the taillight comes on.
Turn the Master switch to Off and remove the fuse.
Final Preparing for Wrapping the Harness
There are a few things left to sleeve. These can be done with difficulty using 4mm sleeving but are easy enough with 5mm sleeving:
The Brown and White wires that go to the rear brake switch need sleeving from the switch to about 3" inside the rear frame crossmember. I normally have already done this as I said before.
The Light Green/Brown wires to the flasher need sleeving from the flasher to about 3" inside the rear frame crossmember.
The Purple/Black and Red wires to the horn need sleeving from about 2" from the end of the wires to about 3" inside the rear frame crossmember.
You might as well remove the harness from the bike for this as the next step is wrapping and that can't be done on the bike.
