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Author Topic: Yet another 79 cb650 charging problem  (Read 1233 times)

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TripleDeuce

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Yet another 79 cb650 charging problem
« on: May 02, 2009, 08:05:07 PM »
I have been battling the charging system on my 79 cb650 for about a month now. I had replaced the stator,and the rectifier with no results. I then replaced the rotor and she charged for about 75 miles and back to no juice. My bike passes all the tests in the clymer manual, but still no charge. I noticed tonight that if I unhook the big plug to the rectifier while she is running the lights get much brighter. Is this normal? I am open to any and all suggestions.. I am a certified marine mechanic, so I am not afraid to get my hands dirty and my weekends stolen.  I am running out of ideas.
« Last Edit: May 02, 2009, 08:33:58 PM by TripleDeuce »
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Offline Hush

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Re: Yet another 79 cb650 charging problem
« Reply #1 on: May 02, 2009, 08:51:59 PM »
Jezz mate welcome to "club CB650 charging problems" ! :(
Many on here been battling this one, I'm hoping that one of us will find the secret to this issue.
I have replaced my stator with a borrowed one which looked a promising start but again no change, replaced the reg/rect with a borrowed unit but no change, have done all the Clymer tests and no problem found.
Interesting you say you replaced the stator and got it charging for a short period!
It is the one thing I have yet to replace, hmm my wrecker has a couple of spares, might borrow one of those too.
If you have been following "Kit's" tale of woe in her HOT START ISSUE thread you will know she has gone into even more depth than me.
I do know mine keeps a charge much longer if I ride with the quartz halogen light off when riding but I like to be seen and for me this is an unacceptable safety issue.
What do you experience if you ride without your headlight on?
Does your bike start OK but after riding it wont restart? or is very sluggish to turn over?
We had theorised that the starter motor could be at fault, then blamed the pulse generators, at this point we just don't know???
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

TripleDeuce

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Re: Yet another 79 cb650 charging problem
« Reply #2 on: May 02, 2009, 10:03:52 PM »
I went out and geeked out on it for a couple of hours, and tried my last available rotor. What do you know, She Is Charging! What do you think about drilling the stator cover to let some of the heat out? I have an extra cover to play with. This the 3rd rotor I've had on this bike within a month. What else besides heat could be killing my rotors?
« Last Edit: May 02, 2009, 11:11:55 PM by TripleDeuce »
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Offline Hush

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Re: Yet another 79 cb650 charging problem
« Reply #3 on: May 02, 2009, 11:41:00 PM »
Hmm well my bike was fine when it was in a dozen boxes, the problems only started when I put it all together and started it up. :)
It charged fine for a start and then the more I rode it the less it charged so maybe you have something, maybe the rotors are duds?
I can get my hands on a few spares, it's one of the few 650 parts my wrecker still has.
Have you noticed any scratching or tracking around the rotor, mine looks like it has flown off at some time and has a nasty shiny inch wide track right around it but I can't see where it would have made any contact with anything solid!
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline Hush

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Re: Yet another 79 cb650 charging problem
« Reply #4 on: May 02, 2009, 11:51:15 PM »
I may have this wrong but from what I have read, the rotor is powered by the two rectifier wires running down to the carbon bushes, this in turn creates a powerful magnet that being spun by the motor revolutions creates the AC power that is sent up the 4 yellow wires to the regulator which turns it to 12v DC and off it goes to battery/lights/ignition.
OK I might not have all that right but that simplistic explanation helps me understand it all a bit more.
So maybe the 30 year old rotors are just worn out, I'd like to know if your bike keeps charging and do you ride with your light on?

                                            Cheers..............Hush
                                                                   New Zealand.
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline manjisann

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Re: Yet another 79 cb650 charging problem
« Reply #5 on: May 03, 2009, 05:02:26 AM »
Welcome to the 650 club!  :)  If you don't mind a bit of reading, a ton of charging information has been covered in this thread http://forums.sohc4.net/index.php?topic=30602.555 by TT and several of the other knowledgeable guru's here, and as a bonus you can check out Hush's kiwi sense of humor  ;) 
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Offline MickeyX

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Re: Yet another 79 cb650 charging problem
« Reply #6 on: May 03, 2009, 08:46:23 AM »
Or this thread. http://forums.sohc4.net/index.php?topic=42826.0  We haven't been on it in a while because most people have been posting on her build thread instead. I will hopefully have a small update on her bike starting issue later today and will post it in the correct thread. Not that I think I will have an answer to what is happening but it is time to update what we've tried and checked since then. The most recent is at on the last 5-6 pages of the build thread.
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Offline Hush

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Re: Yet another 79 cb650 charging problem
« Reply #7 on: May 03, 2009, 08:30:14 PM »
OK have borrowed a rotor and will report back with my findings after I change it out. :)
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!
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