Topic: Starter circuit safety bypass help

[OldGreyBeast]

The previous owner of my 1976 CB550 had done all kinds of stupid stuff with the wiring.  I've got most of it sorted out but am tired of fighting with the clutch and neutral safeties.  What's the easiest way to eliminate these so the starter button just starts it up?  My suspicion is that one of these safety mechanisms is keeping the starter from working.

[BenelliSEI]

Not sure if your cb550 has the same starter motor safety switch as my 1973 Honda cb750K3. Here’s what I did (from an earlier post). I’m sure others will chime in if this is incorrect…… The box on the floor is the safety switch. Have the same thing?

Checked my wiring several times. Lights and everything else worked, but no starter button. Ultimately determined the starter motor safety switch had failed. Removed it, installed the “jumper “ (solid green to green/red stripe) and everything works as it should!

[OldGreyBeast]

Mine doesn't have the starter motor safety switch, just has the clutch and neutral safeties.  The previous owner somehow bypassed the neutral safety (I've been trying to get the neutral light to work for years without success) but the clutch safety is still there and doesn't seem to work.  The wires are very frayed at the clutch lever so I'm guessing it's just DOA.  Where it's at I can't really solder it back together.  I'd prefer it not have any of that safety junk anyway.

[bryanj]

Need to kow how many wires connect to your starter button in the handlebar switch and what colours they are.
Because of its age it is not safe to assume its the same as when built and wiring diagram correct.
Let me know those and i will tell you what to connect where BUT remember the time difference me to you

[OldGreyBeast]

I'll wheel it back into the living room (where I've been working on it due to how hot it is here) after work.  I was fiddling with it during my lunch break.  Probably be later this evening before I get back to you, but I'm not in a huge rush.

[bryanj]

No problem, i suspect 3 wires, colours will help.

[OldGreyBeast]

Kinda hard to see in there but it looks like 4:

Green
Green/Red
Black
Black/Red

[bryanj]

Not seen a Honda switch with 4 or green and green red, is it an aftermarket switch? Is there anything apart from kill switch and start button on there plus do you have and can you use a multimeter

[OldGreyBeast]

I'm honestly unsure if it's an original switch or not.  It's the one that was on there from the previous owner.  The kill switch and start buttons are the only things on it.  I do have a multimeter and the facilities to use it haha.

[OldGreyBeast]

The red/green wire goes to the yellow/red wire on the bike harness.  The green wire goes into one of the 1-to-4 green junctions.  Black goes into a black 1-to-4 junction. Red/black goes to a red/black wire on the bike harness.

[bryanj]

OK can you do a test for me with either a multimeter or a bulb,
See if there is 12v dc between the yellow/red and green with the ignition and kill switch on and starter button pressed

[OldGreyBeast]

Hmm nope, not getting any voltage.

[OldGreyBeast]

Do I just need to ground the red/green wire on the starter solenoid to do what I'm looking for?  The wiring on these old bikes confuses me.  Every diagram I see references a starter motor safety unit, but neither my 74, 75, or 76 CB550s have that.

[bryanj]

You have a very unusual switch and what you ask would not work with what you have.
Taking the 4 wires on the switch you need to check for me
1 with the button NOT pressed the black should connect to the red/black but dissconnect when button pressed.
2  do the green and green/red work opposite, that is disconnected when NOT pressed but connected if pressed.

[OldGreyBeast]

1. This works as expected, black and red/black disconnect when the button is pressed.
2. The green wires don't seem to be affected by the button at all.  The red/green one appears to be grounded all the time regardless of the position of the button.

EDIT: At the solenoid itself, both the g/r and y/r wires have continuity to ground.  The 2 large terminals do not have continuity.  Do I just have a bad starter relay?

[bryanj]

What is supposed to happen is that when you press the starter button the headlamp turns off (black is power in, red/black to headlamp fuse) and power is supplied to the yellow/red which goes to the solenoid which grounds via the red green wire through the safety circuit.
The switch unit you have is not for that bike and without it in my hands i cannot test it to see what would make it work.
Long distance testing is just about impossible mate.
If you can find out which two wires connect when the button is pressed i may be able to help

[OldGreyBeast]

That was exactly what I needed, I got it sorted.  The green wire was connected to ground instead of +12v.  Moved the green wire from a ground junction to a +12v junction and now the start button works like a charm!  I grounded the green/red wire in the headlight harness, that seems to have bypassed the clutch safety.

Thanks for the help!

[bryanj]

This is the big problem with pattern parts, they dont work the same!

[HondaMan]

In the OEM version, you could just unplug it in the headlight.

[Deltarider]

You didn't specify your model. The 'year' is meaningless. If you check the wiring diagrams of the various models CB550, you will see the wiring was different. Always consult the apropiate wiring diagram first!

[OldGreyBeast]

All mine are 550K, the diagrams I've seen don't match up with any of the 3 lol.

[Bodi]

I have bypassed the headlight shutoff in the starter button, the switch contacts usually burn up after so many years of carrying the headlight current and that cooks the plastic internals of the switch. So I just bypass it even if the switch internals look good (this is rare). It doesn't affect starting function in my experience.
To get a direct start you want the solenoid connected directly to the switch. I'm not sure whether your bike switches ground or power, but just connect it so the started button goes to the solenoid instead of through the safety stuff.
If you don't have a safety module it works with just one diode anyway and the starter button switches ground (since the neutral switch does). An open diode failure will allow starting only with clutch pulled in. A shorted diode failure will have the neutral light on whenever the clutch is disengaged but the starter will work in neutral or with clutch disengaged. Assuming the switches all work of course. But all bets are off if a PO corrupts the wiring harness.
I think the safety system is a good thing though. Starting in gear can be a disaster.

[Deltarider]

All mine are 550K, the diagrams I've seen don't match up with any of the 3 lol.

Then PO must have messed up, possibly after consulting the inappropiate diagram. Succes with sorting that out!

[bryanj]

Delta its not the wiring thats wrong its the switch, probably aftermarket for a completely different bike

[Deltarider]

Delta its not the wiring thats wrong its the switch, probably aftermarket for a completely different bike

That is not automatically in conflict with what I posted.