How to do this?

[deltarider]

Soon I have to replace the LH switch unit (the wires through the handlebar type) by another one and I am not sure about the correct working order. Can any of you experienced mechanics tell - preferably in steps 1-n - how it is done correctly?

[McCabe-Thiele (Ted)]

In my short experience of two, threading the wires it is much easier if you have removed the handle bars from the bike.
First time I used a piece of string that passed through the bars and attached it to the harness with insulating tape. If you use silicone spray the wires pull through much easier. When I fitted the switches on the 500 I improved on string by using two long cable ties instead. Also easier done in warmer weather - I had my switches in the airing cupboard overnight then doing the threading through in our conservatory.

[deltarider]

Thank you, Ted.
If possible I'd like to have it in steps, so we will have the correct procedure, also for the rest of the world SOHC Four community and we will only have to communicate a simple link hereafter.
Step 1 would be: open the headlamp and disconnect all the wires connected to the wires coming from the   switch unit. If necessary, consult the wiring diagram of your particular model.
Step 2 Free handlebar from its clamps for easier maneuvering
Step 3 Before removal of the old unit which implies pulling the associated wires out through the handlebar attach... what?

[Oddjob]

I presume you want to replace the broken bottom section that snapped recently. If so I would advise just doing that, removing the wires from the bars usually means the covering of the wires disintegrates especially if the switch is original, the covering goes hard over time and breaks into sections, removing the wires will either mean these sections grab at anything inside the bars and make removing them difficult but refitting them will be a nightmare. It's far easier to just remove the switches from inside the switch and replace the broken part with a new one. Removing the switches is pretty easy with the right screwdrivers, it's just usually 2 or 3 small screws holding them in place, if you feel replacing the bottom section would look odd against the top section replace both, replace the indicator lever and the horn/flasher button as well and it will look like a new switch but without all the bother of threading wires and reconnecting bullet connectors etc.

This is especially true if the replacement is not a genuine Honda switchgear, some of the replacements have the wrong coloured wires, so long as your existing wires are still in good nick and the switches inside the switchgear work as they should it's far far easier to just swap the bodies. Study the new switchgear and see how it fits, take a couple of pics to be sure. I could do that job in 20 minutes or spend many hours trying to thread the wires etc

[deltarider]

Aha! Thanks Oddjob. Actually the switch unit itself is not damaged and all functions work. Also I have fitted already a new lever. It's just that I can't fit my mirror anymore. See pic. Maybe I have not studied it enough. If all the wiring goes from the tophalf of the unit, replacing the bottom half would be a good option.

[McCabe-Thiele (Ted)]

Thank you, Ted.
If possible I'd like to have it in steps, so we will have the correct procedure, also for the rest of the world SOHC Four community and we will only have to communicate a simple link hereafter.
Step 1 would be: open the headlamp and disconnect all the wires connected to the wires coming from the   switch unit. If necessary, consult the wiring diagram of your particular model.
Step 2 Free handlebar from its clamps for easier maneuvering
Step 3 Before removal of the old unit which implies pulling the associated wires out through the handlebar attach... what?

As there are so many different levels of member competence on this site  it's often difficult to pitch a reply at the right level.  I usually assume that we have read say a Haynes Manual so are aware of preliminary basics. You did say steps 1 to n so sorry for my lack of detail I just went for what is often the problematic part.

If you no longer need to remove the wires from the bars that's great.  Personally if  trying to solder in a new switch to the old loom I would do that off the bike with the bars on the on bench. I try to take photos of the wires inside the headlamp bowl plus I would write down the colour and sex of the connector where applicable including if there are than on wire on say a female connector. Colours also fade so a light grey might look like a light blue etc when you check against a wiring diagram. If you are fitting a new switch I would use the wiring that came with it resolving any colour mismatch rather than trying to solder old oxidised wires to a new switch - depends how good you are at soldering I guess.

I would  PS I hate doing electrics but sometimes it can be easier than you expected.....sometimes.

[deltarider]

Thanks again, Ted. I had to do quite some research for the details, only to find out a day later there were even more. Maybe I shouldn't bother you guys with it, as the CB500K2 GENERAL EXPORT was not imported in the UK*. On the other hand, the model CB750K6, which had the same switch unit, was. So here are my findings:
The original 35200-341-600 had nine wires:
orange
light blue
white
blue
grey
black
light green
brown/red
brown/blue (buzzer)
The repro https://honda4parts.nl/product_info.php?products_id=2621 is slightly different. It doesn't have the buzzer wire. That would not have concerned me, as I already in 1980 disconnected that annoying thing. It's for another reason I don't like to buy that repro. Both my left and right switch units have faded nicely over the years and to have a brand new and pitch dark one, only on the LH side, would not look nice.
The unit my friend has on offer, is faded and almost the same as the original 35200-341-600, but lacks that same brown/blue wire for the buzzer. Again that does not concern me at all. What I still have to find out however (sigh) is: will my friend's unit accommodate the separate clutch lever switch wire (35360-341-000)**? It allows you to start the engine, with the transmission engaged, as long as you pull the clutch lever. It's an extra this model had, much appreciated by me.
*Curiously enough the appropiate wiring diagram is called: U.K.-EUROPEAN TYPE.
**It's #6 in the pic. https://images.cmsnl.com/img/partslists/honda-cb500k2-general-export-f-3-handle-lever-switch-cable_big3IMG01171125_2021.gif

[Oddjob]

They all have the clutch switch when the switchgear looks that way, only the 500k1 and early 750 didn't get it.

No soldering involved Ted, all the switches come out with the wires attached, they just drop into place and a plate covers them to stop them from moving, it's the plate that's screwed into the body not the switches.

Yours friends switchgear body will be the same as yours, so just swap the body

[deltarider]

I presume you want to replace the broken bottom section that snapped recently. If so I would advise just doing that... [...] It's far easier to just remove the switches from inside the switch and replace the broken part with a new one. Removing the switches is pretty easy with the right screwdrivers, it's just usually 2 or 3 small screws holding them in place, if you feel replacing the bottom section would look odd against the top section replace both, replace the indicator lever and the horn/flasher button as well and it will look like a new switch but without all the bother of threading wires and reconnecting bullet connectors etc. [...]

Tomorrow I am at my friends place to have a look at things. Did I understand right we can just replace the bottom part and screw the rest of my switch gear on top if it? How about the horn/PA and the hi/lo switches. They are in the bottom part, right? Sorry to bother you again, Oddjob, but I like to come prepared when I'm there.

[Oddjob]

It's quite easy to understand DR, the switches inside the switchgear are self contained, they will come out as a series of blocks so to speak, the blocks are screwed into the body of the switchgear with retaining plates used to keep them in place. On the bottom of the switchgear are 2 blocks of switches, the horn/pass switch is one block, the hi/low is another. The horn/pass is contained in a small box, it usually comes out as one piece but sometimes the lid comes off, so long as it comes out without all the guts inside spilling out you just unscrew the button on the outside, pull off the button (be careful of the halfnut that will still be inside the stub of that switch, push it out and refit when it's in the other switchgear) then slide the box up and back, simple when you see how Honda fitted it. The Hi/low switch is even easier, it never seems to come apart when being removed. Just a small screw to remove, push the switch out from the front and refit the same way as it came out.

The only hard part about doing this is getting the small screw that holds the horn/pass button on to come out, a good JIS screwdriver is needed as they tend to rust in the head of the screw and the screw head rounds off. I have replacement screws and halfnuts in stainless steel now to stop them doing this.

I'd say 30 mins tops to do this job. Harder to describe than to do.

If you have your mates switchgear to hand, try removing and refitting the blocks on that before splitting your switchgear, test and see what the problems may be whilst it's easy to see what you're doing, you'll find that doing this job is a lot easier than you thought it would be. I'd advice checking all the wires on the switches you're going to be using before refitting them, especially on the horn/pass as I've seen them starting to fray where they are soldered onto the switches inside. So long as those connections are ok then it's a very easy job. You may have to pull out a little wire from the bars in order to make it easier to work.

[deltarider]

Thank you very much!

[deltarider]

It worked! Thanks to you guys and Gerrit and Henk here. We only exchanged the lower half of the unit. It was a bit of a hassle. I had worked on the PA function a couple of years ago. BTW, the little screw that secures the combined Horn/PA knob from underneath, is the smallest screw I have ever seen. The PA function of that knob still needs my improvised solution to prevent it sliding to the right unintentionally, but I am used to that.
Tip: when you have to do this at the handlebar, have something underneath it, out of precaution to prevent tiny parts fall to the floor. Believe me, you will drop one of those tiny screws.
Thanks again!

[Oddjob]

You want a stainless steel screw and nut DR. FOC just pay for postage. Was the spring ok on the PA button, there are 2 inside that block, one for the horn and another to return the pass when you've used it.

Wasn't as hard as you expected I'll bet. If you use magnetic screwdrivers it saves you loosing the screws as they come out.

[deltarider]

[...] Was the spring ok on the PA button, there are 2 inside that block, one for the horn and another to return the pass when you've used it.

The pass still doesn't return, but I can live with that. A couple of years I improvised something that will prevent sliding it to the right unintentionally. Many times on entering a tunnel I would detect Hi beam was on. Standard in those days I was running LO as daytime running light. So... if both filaments were on, knowing: 60 and 55 Watts, statements across the pond, that the CB500/550 charging system is insufficient, is contradicted once and for all. Anyway, didn't want to bother my friends with it anymore. In spite of their age - they are both older than me -, their eyes are better. Not only my eyes water - this is a condition when your eyes are too... dry - and today there were so many pollen in the air, I couldnt have done anything by my self.
[...]

If you use magnetic screwdrivers it saves you loosing the screws as they come out.

Thanks for the offer. Suprisingly after 47 years that tiny screw was still OK. Anyway, there's a new one in now. Much obliged Oddjob. Magnetic drivers are on my list. Hope I will find some Vessel JIS drivers.

[robvangulik]

If you use magnetic screwdrivers it saves you loosing the screws as they come out.

Not if you use stainless steel nuts and screws...