Topic: 1976 CB550K wiring harness question

[bryanj]

The usual reason that green wire melts is a bad contact on the ground wire at the engine end makig full starter current go through the small green wire.
People have the brackets powder coated/painted and dont remove it both sides where it touches engine case and cable

[Bodi]

"I have the same problem. Can you explain  a bit why the diode is a better option than the relay/switch?"

The SSU is unnecessarily complicated.
The idea is to disable the starter when the bike is in gear with the clutch engaged, and a switch had to be added to the clutch perch. The SSU is basically an electronic switch (an or gate) that enables the starter if in neutral or the if clutch is disengaged (or both).
Someone realized that if the clutch switch directly grounds the solenoid and the neutral switch grounds it through a diode, the result would be identical, simpler, and cheaper. And if it failed, it was a 50 cent diode (OK, the Honda part is way more but that's what a good replacement from Electrosonic <older Toronto nerds will know> cost me) rather than the SSU module. The diode is really there to make the neutral light work normally, without it you still have the safety interlock but the neutral light comes on with clutch disengaged.

[amitr0]

"I have the same problem. Can you explain  a bit why the diode is a better option than the relay/switch?"

The SSU is unnecessarily complicated.
The idea is to disable the starter when the bike is in gear with the clutch engaged, and a switch had to be added to the clutch perch. The SSU is basically an electronic switch (an or gate) that enables the starter if in neutral or the if clutch is disengaged (or both).
Someone realized that if the clutch switch directly grounds the solenoid and the neutral switch grounds it through a diode, the result would be identical, simpler, and cheaper. And if it failed, it was a 50 cent diode (OK, the Honda part is way more but that's what a good replacement from Electrosonic <older Toronto nerds will know> cost me) rather than the SSU module. The diode is really there to make the neutral light work normally, without it you still have the safety interlock but the neutral light comes on with clutch disengaged.

Being from computer science background, this OR gate explanation made it so easy to understand. Thank you

In case one needs to swap out the SSU with a diode, how should the wiring be done?