Diode problem maybe

[Trigger]

I have been going through some stock bike that need to be ready and put up for sale.  Pulled a CB550F2 UK bike out and linked it up to a battery, everything works apart from the starter motor will not turn over. Changed the solenoid 3 times and still nothing  Then i clicked that this unit has the clutch operated switch , Pulled the clutch lever and pressed the start button and the solenoid and starter motor are fine. So what we have is the neutral light is on and will go out when selecting gears but, still have to pull the clutch lever to get the solenoid to engage.

Had a look at the wiring diagram and it points out that it has a diode. The problem is i can't find any such diode or even the wires for a diode.

Help needed as I am shite at wiring 

[K2-K6]

Has it got a sidestand switch or wires for it?

If so,  it runs in a loop for that to force you to put up the stand before putting in gear.

[SteveW]

The only purpose of the diode is to stop the neutral light coming on every time you pull the clutch in.
You can bypass the diode with a bit of wire but you’ll get the above issue. You still shouldn’t be able to start the bike with the stand down and clutch pulled in if it’s wired properly.

[Nurse Julie]

The only purpose of the diode is to stop the neutral light coming on every time you pull the clutch in.
You can bypass the diode with a bit of wire but you’ll get the above issue. You still shouldn’t be able to start the bike with the stand down and clutch pulled in if it’s wired properly.

Never seen a CB SOHC/4 with a side stand switch 🤔 Are they fitted to any of them?

[SteveW]

I just assumed there was one, never looked.

So it’s just the clutch switch, if the clutch is pulled in and you are in not in neutral bike will start.

You don’t even need the proper Honda diode, a 1N4001 or 1N4004 1Amp diode or similar will work.
That’s what I used, just soldered some wires with crimps on the end.
On my 74 I had the old type safety box unit thing, just ditched that and replaced with above diode, works exactly how it should.

[Bryanj]

As i remember it its a brown revtangular thing in the coil area trig, but dont hold me to that
May have a used one about will try to find tomorrow mate

[AshimotoK0]

Sh*tty image but shown here


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[Trigger]

Cheers for that Ash 
That gives me the location were the wires should be on the loom. After a little investigation and surgery on the loom, I can now see were the wires have been cut off. So, now just a little soldering to splice another on in from a old loom 

   

[deltarider]

On mine the diode is behind the left side panel where all the electrickitry sits, but that is a European CB500K2.

[Erny]

On mine the diode is behind the left side panel where all the electrickitry sits, but that is a European CB500K2.

Have the same on my 550K1