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CB550 not charging

Reid

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The Peoples Republic of North Carolina
I have been working on my brothers 73 500 (has a later 550ss motor) for the last couple of months, and today we went for the first ride and made it 3 miles... it ran long enough to run the battery down. The bike has a pamco ignition, a siriuscon reg/rec, and was charging two days ago when I went over everything. When it quit I checked those bullet connectors that like to unplug on their own, the fuse, and the reg connections nothing jumped out at me. Any ideas?
 
Need to do basic diagnosis. First fully charge the battery. When running what is the charging voltage at 2000 to 3000 rpm? The old hondas dont charge at idle....or very very little. What is siriuscon reg/rec? Is it still a stock type setup? If it is stock type regulator/rectifier charging system that will be your problem 9 times out of 10. You already checked the connections. Also, it only took a 3 mile ride to run the battery down? I have rode for over a half an hour without a charging system, just on the battery. A lot of vintage road racers dont even use a charging system, just the battery for the entire race. Is it possible your battery is bad and the charging system can't keep up with the battery. If it is sulfated or has a shorted cell the stock charging system wont keep the battery charged. Just some thoughts. Come back if you have more questions:thumbsup:
 
The siriuscon reg is a solid state unit http://www.siriusconinc.com/pro-detail.php?pid=&product_id=3510, as for the battery we were running down some of the electrical gremlins earlier (headlight not plugged in, brake light switch adjustment, lots of starting) so that could be the cause. However I had a very similar problem with my xs650 a few months back and found out that my regs (yes plural) had poorly crimped connections and did toast a battery or two, his reg appears ok but I have only done a visual on it. When I checked the charging volts a couple of days ago I did get 13 and change with some throttle
 
Connectors are highly unreliable...but another thing it thought of was...any chance between the last time it ran fine/charged and now that you welded on the bike..or had an arch while doing wiring? I learned that kills vreg by experience...lol
 
Connectors are highly unreliable...but another thing it thought of was...any chance between the last time it ran fine/charged and now that you welded on the bike..or had an arch while doing wiring? I learned that kills vreg by experience...lol

I have but I cant remember if it was before or after I checked the charging V's. Any ideas on how to check a solid state reg/rec resistance, diode, etc.?
 
I just jump started it and checked the V's at idle its 11.xx add some rpms and it goes to 14.0x. Went for a ride around the neighborhood and all was well, we plan to go around town in a little while and see how it goes....the trailer is hooked up and ready to come pick it up if need be

I will post the results
 
Oh yeah. It was me.

Logged a handful of miles and it stayed charged. I kept an eye on the tach and tried not to let it sit at idle for very long (at stoplights etc). I guess keeping the RPMs up and maintaining a charge is key.

I did lose the speedometer somewhere along the way. We haven't looked at that yet.
 
Seems like some helpful tips here. Can someone clarify 1) what/where are these "reg" connectors? and 2) How to diagnose for a 'bad battery'? I have repeated starting problems with my '78 750, and it is either leaking current, poor charging system, or shot battery (although I am able to charge it to 12.6+ V).
 
Google cb750 voltage regulator for an image of one.. Then find the 3 wores leading to it...blk,grn & wht. To test batt I would charge it and test voltage a few hrs later..if it drop more than 1v than its prolly crap
 
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