CB650 not charging — where do I start?

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qonfusion
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Joined: Tue Jul 05, 2016 12:56 pm

CB650 not charging — where do I start?

Postby qonfusion » Sat Jul 09, 2016 3:25 pm

Hi all,

My '79 CB650 isn't charging and has stranded me a few times.

The battery is new and I've trickle charged it several times.

Other electrical issues on my bike are that the brake light (aftermarket, installed by previous owner) does not work when you apply the brake. The taillight does work. There is also a dangling connector at the signal relay, which I'm sure shouldn't be there and could be draining power.

I'm new to ownership for this model and am gathering typical charging problems are linked to the rotor, which fails and then cooks the rectifier. I'm happy to replace what I need to here to rectify (sorry for the pun) this. I'll be buying a testing gauge to help me trouble-shoot.

Any and all suggestions welcome. Also, if you can suggest the best place for parts, or any upgrades (Rick's Motorsports, for example), that'd be great.

cb650
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Re: CB650 not charging — where do I start?

Postby cb650 » Sat Jul 09, 2016 3:57 pm

check the charging first. simple volt meter while running works. after that I cant help. I have never had a prob with charging on all of mine
Did you clean the tank out?!?!?!?!

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Folsoml
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Re: CB650 not charging — where do I start?

Postby Folsoml » Sat Jul 09, 2016 5:06 pm

First, the green wire at the turn signal relay is not supposed to be plugged into anything. It was put there just to confuse people.

Check the ohm reading on the slips rings on the rotor. Somewhere in the 4 ohm range is good. Anything less than that and the rotor is no good.
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qonfusion
Posts: 12
Joined: Tue Jul 05, 2016 12:56 pm

Re: CB650 not charging — where do I start?

Postby qonfusion » Sat Jul 09, 2016 6:44 pm

Folsoml wrote:First, the green wire at the turn signal relay is not supposed to be plugged into anything. It was put there just to confuse people.


Will definitely check the rotor.

Any idea why an LED rear light would cause the red "Taillight" warning bulb at the front to come on then? I've checked and replaced fuses (turn signal fuse was burnt out) but can't make this warning light stop. I worry this is somewhat related to the charging problem.

Thanks for any help.

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Volker_P
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Location: southern Germany

Re: CB650 not charging — where do I start?

Postby Volker_P » Wed Jul 13, 2016 4:13 am

We don't have that in Germany but I guess this warning light should indicate that your rear bulb is gone.
Possibly the LED current is just too low to be detected by that setup.
You may try with an ordinary bulb instead to verify.
But in any case this should not be related to charging.

Measure charging voltage, should rise with rpm to about 15V.
First simple check is if headlight gets brighter from idle to some rpms. It should if charging is all right.
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