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Honda CB750K5 Restoration by Royhall
royhall:
The problem I have with the above is that none of my 3 meters will read accurately at that setting. I'm getting 0.8 with just touching the probes together. But that said the reading across the yellows at the rec/reg is 1.1. So 1.1 minus the 0,8 is 0.3 across all three. So if that logic is acceptable the windings and cables are okay?
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taysidedragon:
--- Quote from: royhall on October 03, 2023, 01:32:42 PM ---The problem I have with the above is that none of my 3 meters will read accurately at that setting. I'm getting 0.8 with just touching the probes together. But that said the reading across the yellows at the rec/reg is 1.1. So 1.1 minus the 0,8 is 0.3 across all three. So if that logic is acceptable the windings and cables are okay?
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--- End quote ---
You have to zero the meter for resistance readings. There should be an adjuster on the side of the meter, mine is a thumb wheel.
AshimotoK0:
--- Quote from: royhall on October 03, 2023, 01:32:42 PM ---The problem I have with the above is that none of my 3 meters will read accurately at that setting. I'm getting 0.8 with just touching the probes together. But that said the reading across the yellows at the rec/reg is 1.1. So 1.1 minus the 0,8 is 0.3 across all three. So if that logic is acceptable the windings and cables are okay?
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--- End quote ---
If you are getting the same reading on all three, then chances are they are OK. Like BigAl says though check for any resistance between the steel stator laminations and any of the three yellow wires. Any resistance at all is bad news of failure or impending failure of the winding lacquer insulation
Oddjob:
Just read an interesting article about testing charging coils like these and his conclusion was that it was a crap shoot, if it tests bad then it's bad but even testing good means it's really only a 50/50 chance of that being true. His assertion was that the only true way to test these type of circuits was to test them dynamically, as in whilst they are operating. Due to deterioration of the lacquer the windings are coated with and the adverse effects of heat and in some cases acidic oil these coatings start to break down when in use due to expansion and loading etc.
I can't say I'm any sort of expert on the charging circuit etc but it makes sense to me and appears to be borne out by published books on the subject like David Sullivans book "Fundamental Electrical Troubleshooting"
royhall:
With my best meter (I can find no way to zero it, problem for another day) it reads 1.1 at the chain case couplings, but as I say, the leads are 0.8 themselves. All three read the same. Bit hard to get a stator reading as the bike is fully assembled. Have checked continuity from the chain case to the plug that connects to the rec/reg and all good. The resistance reads the same from the plug as the chain case. Due to limited accuracy of the meter I will have to assume then that they are correct.
With the engine running, the voltage yellow to yellow should be about 50 volts AC, yellow to earth should be about 17 volts AC. Are these correct values. (Schools in ;D )
Where do I test for rec/reg output, is it the red wire in the same multiplug as the yellows at the rec/reg. When tested it was showing identical voltage to the static battery voltage. I assume then that nothing is coming out of the rec/reg. Still got to test that something is going into the rec/reg.
Heads fried now.
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