400/4 RHS switch - part..

[Matt_Harrington]

My start button has somehow been damaged inside (I have no idea how, as it was fine before I started the engine rebuild!) Anyone got the RHS unit that I can get the appropriate parts from? I'd rather not replace the whole unit if I can.. 

[Oddjob]

Picture Matt? I have some spares for switches. Just need to clarify exactly what it is you're after.

[Matt_Harrington]

This is not my one (finished in the workshop for the day!!) but it is like this:

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The outline in red is the bits I'm after and anything relevant behind....
(The button is loose and does not push in, so something has broken)

[Bryanj]

Its whats inside the switch that matters and alters depending on year

[Oddjob]

You need to open the switch and see what's gone Matt. Behind that button is small spring, the button really doesn't get broken that often. It's just a small piece of plastic with a brass peg on the back, the springs sits on this peg. Behind that is a small bakolite plate, that has contact plate embedded into it. Before it is a small plate with a slot in the middle, this is the source of power for the button, the peg on the button passes through this but the spring cannot so that where the button gets it's spring back from, press the button enough and the peg contacts the contact plate on the bakolite plate.

To me it sounds like the spring has rusted away, this allows the button to sort of slop around and it may in time drop down out of the slot and jam up. Does the button feel it's sitting at an angle?

Just open the switch, the bottom should just hang away without disturbing much, you should be able to see what's the problem just by looking in.

[Multiman]

I'll have a dig around my spare bits box tomorrow pm, but the spring, if nobody comes up with one, is available from Fowlers for a couple of quid. Though I've had a quick look and can't even see the bike listed. I'm sure I got one though.

[Multiman]

Found it. Bryan pointed out its the same as the 500/4 spring part number 35318259000

https://www.fowlersparts.co.uk/search/part/35318259000

If it turns out you need one

[Bryanj]

If its that type the button is available as well, or at lest used to be

[andy120t]

Where do you find parts numbers for switch internals? I have the same bit ( ie the entire starter button/contacts) missing from a 550 but assumed a whole unit was needed.

[Bryanj]

The 400 parts book/fiche is the worst one about, or at least i think so, as its one big picture with pages of numbers.

The very early 500 book i scanned for Ash to post even has the individual carb O ring part numbers and sizes

[Oddjob]

I agree about the 400 parts book, really awful to use.

As Bryan says, the early models parts books tended to show more parts available, like the spring and the button, later models just lumped it all under the switchgear.

The internal plates though Andy were never available separately. The moving levers though, like the indicator lever was though.

Did you know Bryan that the page showing the starter button switchgear is missing from your scan copy.

I have both of the internal plates Andy, the one with the hole through it and the bakolite plate with the contact stud in it.  Not sure if I'll be using them yet, I'm currently restoring some old switches, getting the casings ceramic coated satin black, checking all the wires, maybe re-sleeving the wires as well, if needed replacing the bullet connectors.

The 550K3 BTW uses the same switchgear style but it's different from the 550F, wires are shorter and it has block connectors so the wires travelled outside the bars instead of inside like the F model. The lower housing also has a cutout in it to allow the wires to exit the switch.

[Matt_Harrington]

OK, will open up when I get a moment - I have too many things apart at the moment (not just bikes!!) and I'd rather the switch gear didn't remain partly in bits as well....

[Oddjob]

Let me know what you need Matt as I have at least 2 spare buttons and springs I reckon. Internal plates I most likely have but if yours are broken then you'll need to solder the new ones on. The most likely cause is a broken spring but it could also be the contact plate have broken in two and been pushed back into the casing, however IF that happened I'd still expect the button to feel sprung but just not work. The slot the peg on the button goes through is steel so I don't expect that's broken.

[Multiman]

I'll add myself to the help Matts button issue club.
Yours should you want it, came from Ted originally so maybe we can get it further round the UK
Has got a notch in the case but the button action feels good.

[Matt_Harrington]

Thanks Tim - do you have my address still?