Topic: (Help please) Honda CB650 1979 Universal starter switch

[Xeleon]

Hi guys!

Approaching the final step of my Honda cb650 1979 build and are about to wire in two new control units. These are not Honda specific, so the colors doesn’t add up to the stock Honda front harness. The red connector is right hand and black is left. I’ve studied the diagram thoroughly, but I am so bad with those diagrams. Can anyone help me connect the dots? Or any insight to adding in universal controls to the stock harness.

I’ve managed to locate the following wires (right hand switch/red plug).

Black -> Rectifier/reg.

Green/Yellow -> Taillight/Brake spring switch

Black/red -> fuse box

Black/white -> coils

Brown/white -> ignition/headlight/left handlebar plug

Yellow/red -> starter solenoid

White/green -> LED flash relay/fuse/left handlebar plug

Brown/blue -> fuse

Blue/white -> Left handlebar plug

I can’t seem to identify a ground in the plug. Is this unusual?

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As for my universal handlebar switch plug, I have the following colors. See picture. From playing around with continuity meter, I have identified the following.

Kill switch = Black/white + Green

Start button = Black + Yellow/red

Drive light = Black + Yellow

Park light = Black + Brown + Brown/white

Yellow/green = Ground ?

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So fare I have managed to connect:

Harness - plug
Black -> Black
Yellow/red -> yellow/red
Black/white -> black/white

Does this help in identifying where the rest goes?

I kind man turned my focus towards the headlight dimmer switch and it possibly not being part of my controls. I’ve tried to test light continuity while pressing the starter switch and nothing cuts the circuit.

I’ve added pictures of my switch, wires and harness stock plug.

I really appreciate your input 🙏🏻😊

[bryanj]

Not all switches had grounds, later ones powered the horn and solenoids.
You need to work out with a multimeter exactly what each switch does on what colour then compare to original ones to work out what to connect.

Black in a Honda loom is power AFTER the ignition switch is turned on, RED is live from battery, GREEN is ground

[Xeleon]

Hi BryanJ

Thanks for reaching out.

I figured it was easier to take my control switch apart to trace the wires for functionality.
See attached pictures.

So my black wire in the new plug feeds both light controls, start switch, and auxiliary (which I think is front break light switch), while the green feeds the killswitch/coils circuit.

Yellow would be driving light, brown position light, and brown/white is off switch?

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Coming from the harness, I’ve identified with my mate, who I am sure will tip in here soon.

Blue/brown is 12v+ from the fuse panel. It changes color when leaving the plug to become brown/white and go right back in to the plug and then to the ignition switch to power the parking and tail light in “p” mode

The black wire going into the controls feeds 12v+ to both the start switch and the light, while the solid green feeds the kill switch.  Black/red is 12v from fuse to run blue/white to dimmer switch for headlight in the left. I believe I will need to route the black/red over to the left control plug.

Blue/white from right controls to left control for headlight - so connect blue white in right controls to blue red power from control picture.

Black wire from harness is power for starter button, in which the Yellow/red matches up with the existing yellow red in harness plug.

The above has been trouble shorted with great help from New York, which I am so grateful for! Thanks, K! 😊

Now there’s still a few wires to be connected, so I will continue to tinker around and scratch my head with my diagram. If anyone can be of further assistance, please tip in :-)

[bryanj]

Sorry UK english and US english dont match.
On that RH switch you SHOULD have the following

1 a power into the kill switch
2 a power OUT of the kill switch
1 & 2 connect with kill switch ON, disconnect when OFF

3 there will be 3 wires to lighting switch
1 power in
2 power to side(small front white light and rear light)
3 power to go to main/dip switch on other handle bar

Starter button will have one or two wires that connect when button pushed if two, and connect wire to casing if one

If you can confirm these i will try and tell you what to connect using normal Honda harness colours.

What do yo have on the other handlebar switch.

Remember electrics is easy when its in your hand but at a distance can be damn near impossible

[kerryb]

Hi, I started this with Xeleon on a different forum.  After reading this post, finding a typo from my message, and not being able to “handle” the new controls, I’m confused and have to start over.
 So I’ll start with the kill switch.  Black coming from the bike’s harness is 12v+ for both the kill switch and the starter.  Coming out of the right control you need 12v to the coils which is the black/white on the bike’s harness.

Let me know if the kill switch works with 12v at the coils.

[Xeleon]

Hi Kerry and Bryan

For the RH switch, there’s 1 Black and 1 Green power in. The Black power in splits into 3, so these will be called Black, Blue/red1, and Blue/red2. However, I have 4 wires running to the light switch and not 3.

Kill Switch
Green - power in
Black/white - power out

4 wire lightning
Blue/red1 - power in
Yellow - power out (main)
Brown - power out (side)
Brown/white ?

There is continuity between Brown and Brown/white when the switch is set to middle position (Not main).

Starter
Blue/red2 - power in
Yellow/red - power out

Aux (brake light switch?)
Black - power in
Yellow/green - power out

These two wires are ‘short’ as the connectors spring out from the RH control.

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I am yet to take the LH switch apart and identify the wires. I will do this tomorrow. In terms of functionality, we have

1. Horn
2. L signal
3. R signal
4. High/low beam
5. Push toggle high beam

[bryanj]

Can you do a test for me on the light switch
When the light switch is on main does the power in connect to both the brown AND brown/white or only one of them?

As to the others

Green will connect to a black in the loom

Black/white to same in loom

Blue/red1 will connect to black in loom

Yellow will connect to a loom wire that goes to headlight fuse

Not sure on brown/brown white till you answer first question

Blue/red2 will connect to black in loom

Yellow/red will connect to wire to solenoid in loom which is also normaly yellow/red

Will help with lh switch when you have the collours

NOTE sometimes you need a small jumper wire to connect the switch to the headlamp fuse wire as the may have the same end connectors

[Xeleon]

Hiya

I did the continuity check on what you asked for.

When it is switched to main light, there is only continuity to Brown. Not Brown white.

In terms of LH switch. I have identified the following:

Horn
Green - power in
Light Green - power out

Aux (short wire out from switch)
Green (split from horn) - power in
Green/red - power out

Signal
Grey - power in
Red (right) - power out
Light blue (left) - power out

High/low & push toggle
The blue wire splits into high/low switch and push toggle. I have tested following continuity.

High/low When LOW is toggled, there is continuity between Yellow and White. When high is toggled, there is continuity between Blue and White, however, there is not when toggled low and button pushed.

Blue
Yellow
White

Push toggle these have continuity when button is pushed.
Blue
Black

Does this make sense?

Once again, thank you so much for your time and help. I really appreciate it :-)

[bryanj]

OK, i do not know what your auxiliary switch is, is it a small on/off switch operated by the clutch lever blade?

As to the rest
Horn Green goes to black
Light Green goes to horn with other terminal on horn grounded

Signal
Grey is wire from flasher unit
Other two self explatatory

White connects to the loom wire from other side of headlamp fuse to the wire from RH switch
Blue goes to main beam
Yellow to dip(low) beam

Toggle switch(headlamp flash)

Black connects to a black in loom
Blue connects to Main Bean with blue from dip switch

On th RH switch

Brown connects to rear light(should be brown)
Brown/white connects to the front sidelight if fitted(small bulb in reflector)

NOTE the instuments lights are also normaly brown/white BUT they do not connect at the RH switch you have but in the loom.

This configuration will not use the sidelight/tail fuse in the fuse box but rely on the main fuse, the headlamp fuse will work as it should.

The 650 was not a common bike here in UK and whilst i do have the genuine dealer workshop manual it is not available to me at present.
If you tell me how the aux switch works i will try and sort out how to wire it

[Xeleon]

Hey BryanJ and Kerry

Your help has been so valuable! I really feel like I have got a good grasp of the wiring now.
I have just today installed the wiring and it seems it’s 95% there. Light, high/low switches etc. all works. I am still to hit the starter button, as I need to install carbs and exhaust, but so fare no burned fuses or wires! Fantastic!

I do have one little issue.

My LED blinkers. My tail light, brake light and signals all seem to get powered successfully, including dash indicator, toggled etc., however, my signal lights are constant. They don’t flash. R signal lights up and are constant upon R signal switch flipped and vice verse on L side.

The build has been under way for a year, however, I am confident they flashed before taking it apart and rewiring. As fare as my research has gone, my bet is that the LED flashing relay may be the issue. Maybe it just died from being moved around so many times over the year?

Would the obvious approach be to try an buy a new one and plug in, or might there be another place to look first?

Again, a huge thank you to both of you. The help has been invaluable 🙏🏻😊

[bryanj]

Relays dont normaly fail like that but low battery voltage is a killer for flashers,
You may find start dont spin engine if you have a starter safety circuit or diode

[Xeleon]

I just charged the battery for the first time in a year. Mainly to test circuit as I’m getting a new one. So am I understanding it correctly that low voltage may be enough to power my high beam LED headlight but interfer with the flashing functionality of the relay?I’m not sure if I have a starter saftety circuit or diode.

I believe all my LED light have resistors wired into the units.

I have just measured my battery. It reads out to 12.37v

[bryanj]

Static voltage means nothing, voltage under load is a better indication or more how quickly voltage drops under load

[Xeleon]

I see.

So, I tried to connect a charger to the battery while bike hooked up. The measurement now reads 12.7v. However, I’m trying to run the lights with the engine off. The only thing powered is the signal lights. Even headlight is switched off. Wouldn’t we be able to assume that the signal lights are getting sufficient voltage then?

[bryanj]

Probably but i find led's to be finicky things, try a different relay and see what happens

[Xeleon]

Update

So I created a separate circuit to test the flasher relay and it seems to work as intended. I then went on to test my ground connection from the light, as I see a lot of people mentioning that if the ground is not properly grounded it can cause constant light. I did so by running 1 wire from turn signal ground to battery ground. Separate it out from the harness. Same result. So now I’m back to investigating the white/green power in to relay wire. Would an open end on this wire be able to cause this havoc? I do have a white green at my R handle bar switch that is not connected to anything. Everything else seems to work fine with this wire being left out. Hmm… so the troubleshooting continues :-)

[bryanj]

If there are two connections on the relay one has a 12v pos when ign on(black normally) and one goes to the LH switch(grey?) If there is a third connection it goes to ground, it is important that these wires go to the correct relay terminals or it wont work at best or will short out at worst.
The flasher relay in no way connects to RH switch

[Xeleon]

Alright. Another discovery.

When I check static voltage as previously mentioned on relay input to ground it shows 12.01.

I figured maybe it wasn’t receiving enough to trigger the relay, like you had previously mentioned, so I put my battery charger into jump mode, set it to 12v, and ran that to the relay. Positive to relay. Negative to negative battery terminal. Now everything works. The turn signals flash ans they should. Only after this I discovered the jumper supplies 19.5. So I would essentially have overfed the relay.

Unhooking it and switching back to bike harness, I’m getting same result. Constant light and no flash. No fuses were blown and nothing burned. Probably more luck than anything else.

So either, the battery is shut, the relay is shut (and now requires more power to trigger than supplied), or something is eating away the power that should otherwise have been supplied to the relay.

Note the relay has 49 49a input and pilot light. No ground on the relay.