xs650newb
XS650 Addict
Hey guys,
This question is from my project thread (http://www.xs650.com/forum/showthread.php?p=361188#post361188). Its on the second page of the thread and I'm afraid it isn't getting good visibility by the people that can answer this question.
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Anyways, my (new to me) 1977 xs650 is NOT CHARGING AT ALL. Battery voltage at rest is about 12.5 volts and its not just a surface charge because the battery easily drives the starter motor (I also did these tests jumped to my car battery).
When I say it doesn't charge I mean that literally there is NO voltage change when I rev the bike.
Here is what I have done to investigate:
1) Performed a slap test on the rotor. Successful.
2) Checked alternator brushes. They are each longer than 1/4 inch. They also make strong electrical contact with their respective slip ring
3) Slip ring resistance. Was between 5 and 6 ohms.
4) Stator resistance. Resistance between each combination of white wires on the stator was 0.4 or 0.5 ohms.
5) Voltage at positive alternator brush. The voltage was approximately 0.6 volts less than the battery voltage. Curly suggests this is a problem. I haven't been able to find where the voltage drop occurs but I want to skip this for now because I figure this would not explain why there is absolutely NO CHARGING going on. I figure a low voltage at an alternator brush would cause weak charging, not NO charging. Is this right?
6) Stator output. With the stator PLUGGED INTO the wiring harness I checked the AC Voltage on each combination of white wires. They were all approximately 20 volts.
I think the problem is with the last test. According to Curly's guide it should be about 11 VAC, not 20 VAC. Curly suggests this means a bad rectifier. Is this correct? Can someone explain how a bad rectifier would result in absolutely NO charging.
Also, anything else I should check.
Thanks guys,
Adam
This question is from my project thread (http://www.xs650.com/forum/showthread.php?p=361188#post361188). Its on the second page of the thread and I'm afraid it isn't getting good visibility by the people that can answer this question.
-----------------------------------------------------------------------
Anyways, my (new to me) 1977 xs650 is NOT CHARGING AT ALL. Battery voltage at rest is about 12.5 volts and its not just a surface charge because the battery easily drives the starter motor (I also did these tests jumped to my car battery).
When I say it doesn't charge I mean that literally there is NO voltage change when I rev the bike.
Here is what I have done to investigate:
1) Performed a slap test on the rotor. Successful.
2) Checked alternator brushes. They are each longer than 1/4 inch. They also make strong electrical contact with their respective slip ring
3) Slip ring resistance. Was between 5 and 6 ohms.
4) Stator resistance. Resistance between each combination of white wires on the stator was 0.4 or 0.5 ohms.
5) Voltage at positive alternator brush. The voltage was approximately 0.6 volts less than the battery voltage. Curly suggests this is a problem. I haven't been able to find where the voltage drop occurs but I want to skip this for now because I figure this would not explain why there is absolutely NO CHARGING going on. I figure a low voltage at an alternator brush would cause weak charging, not NO charging. Is this right?
6) Stator output. With the stator PLUGGED INTO the wiring harness I checked the AC Voltage on each combination of white wires. They were all approximately 20 volts.
I think the problem is with the last test. According to Curly's guide it should be about 11 VAC, not 20 VAC. Curly suggests this means a bad rectifier. Is this correct? Can someone explain how a bad rectifier would result in absolutely NO charging.
Also, anything else I should check.
Thanks guys,
Adam
