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Discussion Starter · #1 ·
Hello
My son and I are repairing this bike. We are working to get the charging system working. the reg/rectifier was blown. We replaced that. It looks like the stator/brush assembly is brand new from the prior owner. We have the shop manual. Checking continuity of the rotor it says we should see 4 to 6 ohms between the slip rings we are seeing 1 ohm. Measuring from either slip ring to the iron of the rotor I expected to get a high resistance. I am seeing 10 ohms. This is not a test from the manual so I don't know what to expect on that basis.

Is there a likely failure mode of the rotor that will result in what we are seeing. Do we need to replace the rotor?

Many thanks for any help and advice.
 

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Discussion Starter · #2 ·
Additional information

The bike will run until the battery discharges.

In the manual it starts by asking you to check voltages. With the key in the on position but the bike not running the voltage to the regulator/rectifier is 12 volts.

The voltage across the black and white wires to the stator is supposed to be 12 volts but is only 9.5.

With the bike running the AC voltage between any two of the yellow wires coming from the stator is 0.

Thanks again and happy Father's Day to all!!!
 

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Maybe this flow chart will be helpful:
"electrosport.com/technical-resources/diagnosis-center/fault-finding-guide"

I'm trying to solve a similar charging issue on a Honda bike.

Best of luck!

edit: can't post a true link since my post count isn't high enough
 

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Hi Kirk,

Run jumper wires from the battery to the black/white wires. That way the rotor is given a solid 12 volts, and check the AC voltage at the stator connection again.
 

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Discussion Starter · #5 ·
Hello Scotty and CmonStart, Thanks for the replies. Going down the chart (here at work shhhh don't tell the boss) it points right to the rotor being bad. We will go through it again at home with the bike. I like the idea of running the leads to the black and white to be sure it is getting the proper voltage. We will try that if we think there is a chance the rotor is good. I hear you can blow the R/R and we just bought one so we want to tread carefully.

Again thanks!
 

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Ya, don't let the magic smoke out!

I hate electrical stuff, myself..
 

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Pale Rider
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The Rectifier consists of diodes: they let electricity flow in one direction only -- they cannot be burned out by 12 Volts AC, or DC. The Regulator will only be damaged if you apply AC to it, or you apply excessive Voltage, like upwards of 30(?) Volts DC. The chance of you blowing the R/R, is minimal.

By applying 12 Volts directly to the Stator(?), you will be be fully energizing the electro-magnet inside the Alternator, which will generate full AC Voltage from the Alternator,applying that to the R/R unit, which will convert it to DC, and regulate it down to 15.5 Volts, or less, to run the bike, as well as charge the battery.

If you want a good resource to learn about bike electricity, circuits, troubleshooting their systems, this is a fantastic book:
. It is worth every penny, if you want to understand bike electrical systems. It will also show you how to make some simple tools to use in the process. Cheers!
:coffee:
 
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