Mk3 Handlebar switch gear - clean repair upgrade etc

I have pulled the right switch gear apart and now wonder if there is any good threads on this exact Mk3 electrical components.
Front brake master cylinder leaks look like brake fluid could add to problems as well,

The pilot-head switch, on the upper half of this right hand switch, simply makes a circuit or not. It test with 2.0 ohms resistance when on.
This headlight on/off makes me ask if the pilot light runs all the time the ignition is on?
But my real concern is how far to go with inspection and cleaning ?

View attachment 9158

p400 said:

The pilot-head switch, on the upper half of this right hand switch, simply makes a circuit or not. It test with 2.0 ohms resistance when on.
This headlight on/off makes me ask if the pilot light runs all the time the ignition is on?

Click to expand...

Pilot comes ON when the ignition switch is turned to the 'Ignition and Lights' position.

The Head-Pilot switch selects main headlamp ON or OFF at Ignition and Lights and does not turn the pilot OFF.

p400 said:

But my real concern is how far to go with inspection and cleaning ?

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It's a reasonably simple switch mechanism that will almost certainly benefit from a good clean.

I am also very disappointed with wiring diagrams i see available for this Mk3. It is as if the wiring diagrams are for one electrician to discuss with another electrician, not what is needed for trouble shooting and repairs on Mk3 electrics.
Dashed lines representing trace wires....and which one one is trace? insane.
Wires on these current wire diagrams are not laid out as it is on the bike, simply represented as a diagram that will fit a small space.

WTF? Any help here ?

I would like a 24" X 48" laid out wire diagram as accurately as possible. Color tracing as in as found. Connections/disconnects as found.
Lucas plug connections as built.......and so forth.

p400 said:

Dashed lines representing trace wires....and which one one is trace? insane.

Click to expand...

Dashed lines? Please explain.(Edit: OK I get it, you mean colour diagrams) Trace wires? The first letter is the main colour and the second letter is the trace, for instance, 'NU' is brown/blue, 'WY' is white/yellow.

p400 said:

Wires on these current wire diagrams are not laid out as it is on the bike, simply represented as a diagram that will fit a small space.

Click to expand...

They are schematic diagrams but not difficult to follow.

p400 said:

WTF? Any help here ?

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I will try but I'm not sure why you are having difficulties.

p400 said:

But my real concern is how far to go with inspection and cleaning ?

Click to expand...

So it should be, you do what you have to do to make that unit (or any part) 100% reliable for peace of mind.
I think relays can be a consideration so the switch block functions (where able) are just a power source for relay activation.


Here is a theme that seems popular.
Hey folks, I just bolted a new (electrical thing) to my should be OK old bike not that I have checked it, the dodgy (list of 40+ year old parts) should be OK but this bum electronic ignition (or some other new part) has a miss, what a piece of crap...

Generally you get back what you put in and time and elbow grease will pay off each time you pull back into your drive way with a grin on your face.

On the same topic but off centre.
Honda Africa Twin, switch block problems in wet climates, people taking them back to the shop........... What do I do, I check and prep those parts on my AT when I first read about it... Old bike, new bike, same same, beats walking in the rain ?

I'm certainly no electrical genius and I disassembled, cleaned and reassembled both of the switches on my Mk III.
yes, it's fiddly and tiny and requires some dexterity. All yer doing is getting inside to clean up contacts. Aside
from the mechanical aspects of the switches, it is really just plug and play unless you have wires which became
disconnected inside the switch

Do they work? If so pack them with appropriate grease and refit. My switches were packed with normal grease when I assembled the bike from its crate in 1975. It's unsightly but the switches work fine. There are usually plenty of other areas for improvement to keep you amused.

looked further into my Mk3 righthand switch.

The upper portion is HEAD PILOT.......a simple slide switch.
but it did show a factory crushed wire, or maybe PO maintenance.

At first the rust colors had me concrned , but it looks like rust colored grease.

Bought new dialectric grease "AutoZone"...Permatex product , clear gel. Coated all new clean switch with the stuff.

Disassembled the bottom portion of right hand switch which contains the "off-run-off" red lever and the green start button.


the slider for off-run-off comes out easily , and the contacts can be cleaned easily.

i wanted to pull the two button board and the starter button, but could not budge the tiny board.

Kano Kroil penetrating oil. A few drops and let it soak overnight. The board should
work out without too much trouble. I had everything out of mine so I could clean it
up and repaint it as the leaking master cylinder had nuked the paint. And an A/N
MC rebuild kit stopped all leakage. I had the MC body powder coated. Epoxy spray
paint on the switch body & cover, and then fresh white paint on the indented script (Fill and
wipe flush). Looked like brand new when done. Overall Yes, a bit tedious and hard to do if you
have big hands and fingers.

https://ads.midwayusa.com/product/1...gn=Shooting+-+Gun+Cleaning&utm_content=137203

Moved to the left side , as my turn signals were not working to the right . Left turn signal okay but timing varied on the flash.
looked pretty dirty at first open.

This left side handlebar switch simply lifted apart to allow cleaning.

The turn lever components slide contacts were caked with old grease and were discolored.
they cleaned up easily.

Just get the brand new sparks units, work perfectly, even the wires are the right colors with bullet ends. You can transfer the guts into the Lucas housing if you must as well.

OP, just in case it's missing, I don't see it in any of your pictures, there is supposed to be a detent ball in the HEAD/PILOT slider. The coil spring holds the ball into one of the two V-pockets in the upper housing. Without the ball the spring would be jammed on the first actuation.
The contact buttons would have initially been silver plated.
The starter push button assembly would have been riveted together where a hole is shown in your photo.
All the Best.

OP, sorry my mistake, the rivet hole is located in the depressed portion of the starter push button assembly. The hole shown aligned with the push button does not take a rivet.
All the Best.