Topic: 1976 CB550 Electrical - what is this for?

[Untold]

The connection above the fuses that doesn't join to anything?  What is that for? What should it connect to?

[cwchan]

I think it prevents the green dummy light from lighting up when you pull the clutch lever in between gears

[dave500]

theres supposed to be a diode in that plug,its a small black square with the two male spade tangs.

[Untold]

Hmm ok. What's it do?

[Untold]

No lights come on when I shift, so it doesn't seem to be that

[dave500]

is the clutch switch wired or by passed?can you crank the engine in gear without pulling the clutch in?be carefull trying!

[Untold]

You mean with the electric start?  Nope, doesn't tick over unless I pull the clutch in.  I found a picture of the diode that's missing, but can't seem to find any online for sale. Any ideas where to find one, or a suitable replacement?

Thanks

[Fritz]

Any ideas where to find one, or a suitable replacement?

If you can't find the original Honda part, you could just buy a diode (type 1N5400) and crimp on connectors. The negative pole (white ring) connects to the light green/red wire.
The diode itself costs between 5 and 20cents. If you can't find a 1N5400, you could also use the higher voltage versions (1N5402-1N5408)...
RadioShack should have them in stock.

[Untold]

I'm just kind of confused why it doesn't seem to affect anything?  I don't believe it's ever been there, under my ownership.  I can't start the bike unless it's in neutral and the clutch is pulled in, which I believe is the way it should be.  Isn't that what this diode is supposed to be for?  Should I even bother sourcing a replacement?

[dave500]

if the bikes running fine and works as it should dont worry about it.

[TwoTired]

The diode in the start safety circuit keeps the neutral light from going bright when the clutch is pulled in, yet still allow the trans being in neutral to E-start regardless of clutch lever position.

Normally, you should be able to electric start the bike when the trans is in neutral OR the clutch is pulled in or both.

You can't kick start the bike unless it is in neutral and the clutch out (or engaged).

[Untold]

Thanks guys, sounds like I can just forget I ever noticed it. Sorry if it's a dumb question.  First motorcycle and all.

[TwoTired]

Thanks guys, sounds like I can just forget I ever noticed it. Sorry if it's a dumb question.  First motorcycle and all.

It's not dumb.  It's a part that should be there.
If you stall the bike in traffic, you'll wish you had the diode.  So, you can just pull in the clutch and e-start very quickly while still in gear.  Rather than hunting for neutral first while the cars buzz around you and honk to increase the annoyance factor.

[Mooshie]

Thanks guys, sounds like I can just forget I ever noticed it. Sorry if it's a dumb question.  First motorcycle and all.

It's not dumb.  It's a part that should be there.
If you stall the bike in traffic, you'll wish you had the diode.  So, you can just pull in the clutch and e-start very quickly while still in gear.  Rather than hunting for neutral first while the cars buzz around you and honk to increase the annoyance factor.

+1...been there before.  Mine is the same as yours Untold, won't start unless in neutral.  I just work really hard not to stall

[Fritz]

It's not dumb.  It's a part that should be there.
If you stall the bike in traffic, you'll wish you had the diode.  So, you can just pull in the clutch and e-start very quickly while still in gear.  Rather than hunting for neutral first while the cars buzz around you and honk to increase the annoyance factor.

IIRC, the diode is just a ground path from the solenoid to the neutral switch preventing the neutal light to glow whenever you pull the clutch.
If it's missing, you will still be able to use the e-starter by pulling the clutch. The clutch switch sits directly in the start button/solenoid circuit while the diode is coupling in the neutral switch as a second ground path blocking the neutral light from ground through the clutch switch. (hard to explain without a diagram at hand)

Untold: Replacing this diode will let you e-start the bike in neutral without pulling the clutch.

Diode missing: Starter will only work with the clutch pulled
Diode in place: Starter will work with the clutch pulled OR in neutral (or both)
Diode reversed: Starter will only work with the clutch pulled, neutral light will shine whenever you pull the clutch
Diode substituted with a piece of wire: Bike will start with clutch pulled OR in neutral, neutral light will shine whenever you pull the clutch

[bryanj]

Fritz, the diode is nothing to do with the brightness of the light it's all to do with the safety start circuit so that if the light is not on you have to pull in the clutch for the electric start to work