Replaced rotor, still have a problem

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xs650newb

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Hey everyone,

FYI, this is for a 1977 stock bike.

My battery died last saturday and upon investigation it turns out the slip ring resistance was ~1.5 ohms.

So I got a new rotor from custom rewind in the mail today and slapped it on. Before I put it on I checked the slip ring resistance and it was 5 ohms. Nearly perfect.


After installation I performed two tests.

1) I turned the key to the on position and measured current leaving the battery. It was 5 amperes with no lights on. That is too high.

2) I started bike and checked voltage on battery. It was 17 volts. I immediately killed the bike.


So what gives? It looks like I am overcharging. How can I be getting 5 amperes through the rotor when the resistance is 5 ohms and the battery is 12.7 volts. I should be getting somewhere between 2 and 3 amperes. No more.

Is it possible my voltage regulator is bad. Furthermore, is it possible that a bad voltage regulator prematurely killled my first rotor?

Best,
Adam
 
Hi, Adam. You sure don't seem like a 'newb' anymore. Seem to have a good grip on things.

Anyway, that 5 amps would be about right if one of the ignition points is closed. Here's some excruciating info:

http://www.xs650.com/forum/showpost.php?p=363526&postcount=116

The regulator, if stock contact-point type, could be stuck. Tapping on it while the engine is running may unstick it. Temporarily unplug it to confirm that it's the problem...
 
I agree with TwoManyXS1Bs....................suspect the regulator is stuck............ sending full current to the rotor.May have melted contacts together, when the rotor had only 1.5 ohms.

The other possibility is the regulator has lost its ground reference. May be a good idea to confirm the ground is solid.

You can open up the regulator and have a good look at the relay and contacts.

If it was my bike, I would replace the old regulator with a VR-115 automotive regulator.
 
Thanks guys.

Do I need nylon screws for the vr115 mod on a 1977 bike? I saw one post where the answer was yes and another where it was no so I just want to confirm.

Best,
Adam
 
Awesome. Makes my life a bit easier.

I'm going to inspect the stock VR to see if the contacts are stuck closed but regardless of what I find I'm gonna go with the VR115.

Best,
Adam
 
I read your post, Im sure glad they have improved the charging systems. I 01 spirit will run and run without running out of juice.
Excuse my lack of knowledge of the xs650s Ive just been working on my first one last few months and I find a lot of problems on the charging systems of them posted here on the forum. I would think that a machine running could produce enough power to sustain it self.

I still have not run on any posts regarding my 76 xs and using the vr-115 regulator.
 

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