I am new to the forum. So far I am happy with it all. So many tech tips. I have a 1981 CB650. The battery died on me the other day going home from work. I drive 50 miles one way! Had to wait for trailor. I connected my multi meter to the battery after charging overnight. 12.4VDC. Started bike then checked at different RPM's. Seems to get up to 14.6VDC. At around 4500RPM's it drops to 12.2VDC. I noticed the headlight go dim at higher RPM's. My test results were good on the Reg./ Rectifier. Cleaned the rotor and checked brushes. Still no luck. Anyone have any ideas? Gas is almost $3.50gal..
Thanks.
Charging System
Charging System
Tunes81CB
Sounds like your rotor windings are coming apart at high RPM. I can't think of anything else that would kill the alternator at high RPM.
Just a note for future reference: If you get stranded due to a "dead" battery, disconnect all of the fuses below the ignition key and you'll make it quite a bit further. I drove for a few days like that when my alternator wasn't working. You'll have to push start it but at least you won't have to trailer it home.
Just a note for future reference: If you get stranded due to a "dead" battery, disconnect all of the fuses below the ignition key and you'll make it quite a bit further. I drove for a few days like that when my alternator wasn't working. You'll have to push start it but at least you won't have to trailer it home.
- holysmokes
- Posts: 41
- Joined: Tue Apr 17, 2007 7:03 pm
- Location: nova scotia
left hand engine cover, under it is the charging rotor, use a multi meter, check for resistance across the slip rings
should be 4.4 ohms
http://cgi.ebay.ca/Honda-cb-650-750-900 ... dZViewItem
should be 4.4 ohms
http://cgi.ebay.ca/Honda-cb-650-750-900 ... dZViewItem
- holysmokes
- Posts: 41
- Joined: Tue Apr 17, 2007 7:03 pm
- Location: nova scotia
Welcome here!
I agree that it looks like a rotor rpm problem. One could repeat the measurement at the regulator input side just to be sure.
Rebuilt rotors quality may be fine or poor dependent on who did the rebuild. In case you know nothing about the rebuilder, I would prefer an old original one.
One needs a spare rear axle for the described procedure.
I agree that it looks like a rotor rpm problem. One could repeat the measurement at the regulator input side just to be sure.
Rebuilt rotors quality may be fine or poor dependent on who did the rebuild. In case you know nothing about the rebuilder, I would prefer an old original one.
holysmokes wrote:http://www.cb900c.net/forum/viewtopic.php?t=899
One needs a spare rear axle for the described procedure.
- holysmokes
- Posts: 41
- Joined: Tue Apr 17, 2007 7:03 pm
- Location: nova scotia
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