Topic: Charging system issue 1975 Honda 550/4

[43and countiing]

We are about to begin cleaning every connector. Still an question: What should the resistance be throughout the system vs just from the rectifier/regulator to the battery? What should every wire be at or below?

[43and countiing]

Great help thus far and we start the connector cleaning tomorrow. We are wondering if there is a total system expected resistance vs just the wires from the regulator and rectifier to the battery? What should the resistance for the system be, as measured between any connections?

Thanks in advance

[TwoTired]

Great help thus far and we start the connector cleaning tomorrow. We are wondering if there is a total system expected resistance vs just the wires from the regulator and rectifier to the battery? What should the resistance for the system be, as measured between any connections?

Thanks in advance

State what tool you will use to measure this.

Here's ohm's law.  E= IxR.  (Basic electrical formula)

Normal total system draw is 10A with lighting on.   We know voltage, E=12v, and current I=10A.  Solve for resistance.  R = E/I.  R= 1.2Ω total system resistance.
With lighting off, let's say there's a 5 Amp total system draw.  Repeat math process, and no big surprise, the total system is twice the previous resistance. 2.4 ohms.  Lower resistance demands more current given the same voltage potential.

To cause a 0.5v voltage drop in a circuit and find resistance to cause it, you need to know the current being drawn through that circuit.
The black wire voltage distribution supplies all switched power (voltage and current) throughout the bike. 
If we assume that lighting is off and 5 amps is being drawn,  R = E/I.  Then 0.1Ω causes that voltage drop.  Double that resistance to get a 1V drop.  0.2Ω   For a difference of 0.1Ω

Now you must ask yourself if your measuring apparatus and probe technique is capable of indicating precision to that degree.
Contact of probe to test point can have that much resistance, even if you discount the meter lead connection and it's resistance.
What does your meter's specification say its accuracy is?

Do you have a Wheatstone Bridge that is capable of measuring such small resistance variations?

Perhaps now you can understand, why a voltage drop is a more commonly useful knowledge point to use in troubleshooting.

Cheers,

[43and countiing]

Fingers crossed while waiting for the weather to actually become rideable (Mid-May), we cleaned the connectors surrounding the voltage regulator etc. Had to replace a ground that was fried, and the fuse box. A few connectors were really nasty, but overall for being there 45 years, not horrific. Also replaced a bad repair I had done going to the right rear taillight. Prior to this work, we were getting voltage reads of 16 when revving the engine. After, our range at idle was about 13.5, and revving with the headlight on it was a very steady 14.3 or 14.4. Never went higher. So the proof will be in a long ride, but it would appear your guidance was dead on, and I thank you for your time and sharing your knowledge. I'll let you know when I take it out if anything changes.