Charging System Problems. I think!

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Charging System Problems. I think!

Shaha kuvan
First any help I might be able to get from this forum will be greatly appreciated. OK I'm not an experienced bike mechanic by any means. I just bought what I was told was a near perfect 1980 CB750K. And other than this problem it seems to be. So why do I think the problem is in the charging system? Because where I bought this bike is about a 50 minute ride from my house. The man that I bought it from told me the battery is new and it appears to be. I rode the bike around his neighborhood for a while before I bought it. And it purred like a kitten. So I rode it home and it did fine on the interstate. As I exited the interstate and got off on the side road to my house, it died at a stop light and the battery didn't have enough juice to restart it. I did get it pushed started and got it home. So I put a charger on the battery and tried starting it the next day and it started fine. OK to shorten this up a little, the problem I'm having is it seems that the bike will run fine, but is running off the battery and after about 30-40 minutes that charge is used up and it will die and not restart unless the battery is recharged. I've checked the battery with a volt meter while the bike is not running and I get ~12.5 volts. When I start the bike and run it up to ~4k RPM and check the battery I'm getting a discharge of about 11.8 volt and know that is should be a charge of about 14. I traced the wire coming out of the alternator to where it connects into the wiring harness and tried to check the voltage there while the bike was running and couldn't get any reading on any of the leads. There are 5 leads there, 3 yellow, a black and white. OK so my thought was it's either the stator or the brushes or the rotor which I was going to buy but they are very expensive. A friend of mine at work, who is pretty good with motorcycles, told me that, that might not be the problem and to try here (this forum) first. So anyone have any thoughts?
Thanks  
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Re: Charging System Problems. I think!

Re-run
Administrator
http://www.adrive.com/public/6017e2e0f1070c863e86e24b741e8cbadedc4b2ccaf24c42e9c3fa41df93565e.html
That is a doc that may help you trace things out a bit. otherwise go into the manuals section and download the manual and it will have ways to check the charging system.
The ride IS the adventure. The destination is just to get gas!
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Re: Charging System Problems. I think!

Shaha kuvan
Thanks for the chart Re-run. One question and this may seem like a dumb one. They keep referring to "RR" on this chart. What does the RR stand for?
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Re: Charging System Problems. I think!

Shaha kuvan
In reply to this post by Re-run
OK disregard the last post. I found it.
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Re: Charging System Problems. I think!

vern401
I would use a multimeter and set it to AC volts setting. Then measure the reading comming between the 3 yellow wires. Wire 1 to 2 Wire 1 to 3 and wire 2 to 3. What are the volts AC with the bike running?
Nice chart Re-Run will keep a copy of it.