Topic: '82 CB650SC Nighthawk Charging System Issues

[Logite]

Hey guys. I've had my bike for about 3 weeks now and under a myriad of other issues with the bike I just recently found out there's an issue with the charging system. I haven't had any mechanical experience up until past week.

Nonetheless I've tried testing the stator with no success. I've tried using a digital multimeter to read the resistance on the regulator rectifier but it only flashes a number for a few seconds on the lowest setting. On the higher settings nothing shows up at all. I haven't been able to check the specific gravity due to no places around here carrying a hydrometer or even TESTING. I read 12v or so when it's charged overnight. The only thing I can think of is replacing the whole #$%*ing electrical system.

I've tried testing the stator but the numbers fluctuate wildly. I'm confused as #$%*.

Any ideas?

[WFO]

First off take a deep breath and be patient

http://forums.sohc4.net/index.php?topic=38585.0

[NPHLYT]

I just sold my 1982 650 Nightchicken 2 weeks ago...... The only thing that was wrong with it was that it needed a rotor (charging system), but it only showed it's problem at idle.

First thing you need to know is that that bike does not charge until into the 3k RPM range (I cannot remember the number). Everything else is gravy, get a Clymer's manual and sit back with a cold one(s) and enjoy the read. They are pretty simple bikes, especially when your mechanic's shop is only a few miles away and he used to race CB750 drag bikes back in the day.

[Logite]

I realize it charges over 3k rpm. The battery won't charge. I've used a multimeter to check the terminals and I got 12v idle at a full battery charge but when I rev it it won't go above that.

[WFO]

A series of tests will find your problem the search function is our friend.

[NPHLYT]

Dumb question... Have you had the battery tested? Have you checked the fluid level in the battery? Mine would not keep a charge for longer than a week, I took it to Batteries Plus and they tested it free, it was bad. After I put a new battery in it it was fine.

[Logite]

Dumb question... Have you had the battery tested? Have you checked the fluid level in the battery? Mine would not keep a charge for longer than a week, I took it to Batteries Plus and they tested it free, it was bad. After I put a new battery in it it was fine.

I'm going to test it at autozone then try to buy a hydrometer. Will update with results.

[NPHLYT]

The Autozone (both of them) near me could not test it, they said they were afraid they would burn it out. I found a place that deals with batteries.

Lets hope it is just the battery. If you need a rotor there is a guy who sells rebuilt Nightchicken rotors for like $145 plus core. I have not been able to find the site, remind me in a few weeks when I get home.

[Logite]

make sure it's nothing simple first like worn brushes etc.

Again I just got into riding so I wouldn't know what simple would be. Worn brushes, check. What are worn brushes? What else should I check for?

[NPHLYT]

My best friend has turned out to be Clymers, they make a great manual.

[TwoTired]

Based on recent troubleshooting, I highly recommend that you find the black and white wires going from regulator to alternator, disconnect them and measure the resistance of the alternator rotor with a DMM.  If lower than 4.9 ohms or higher than 6 ohms, you've found the problem.


Cheers,

[WFO]

make sure it's nothing simple first like worn brushes etc.

Again I just got into riding so I wouldn't know what simple would be. Worn brushes, check. What are worn brushes? What else should I check for?

Best thing you can do is jump in and learn this site and it's people are the best and they will walk you through it and in the process you get to learn and be able to impress chicks.

[Logite]

I got my battery tested today and apparently the whole thing was corroded. I bought a new one and put a multimeter on it when I revved of and the volts still wouldn't raise past 12. I can't check the brushes without a flywheel puller nor can I access the alternator. Any ideas where to go from here?

[scunny]

you don't need to remove the rotor to check the brushes, they are in the cover as per weird beards pics.
and if you do want to remove the rotor, your rear axle is the right thread..just wind herin give it a tap and the rotor should drop off

[TwoTired]

I got my battery tested today and apparently the whole thing was corroded. I bought a new one and put a multimeter on it when I revved of and the volts still wouldn't raise past 12. I can't check the brushes without a flywheel puller nor can I access the alternator. Any ideas where to go from here?

Yes, see:
http://forums.sohc4.net/index.php?topic=39605.msg408622#msg408622
  You can check this at the connector for the Rreg/rect.

[Logite]

I got my battery tested today and apparently the whole thing was corroded. I bought a new one and put a multimeter on it when I revved of and the volts still wouldn't raise past 12. I can't check the brushes without a flywheel puller nor can I access the alternator. Any ideas where to go from here?

Yes, see:
http://forums.sohc4.net/index.php?topic=39605.msg408622#msg408622
  You can check this at the connector for the Rreg/rect.

What do you mean by DMM? I have a digital multimeter but I'm wagering it's a tad flakey. Either that or the stator is screwed. I took apart the alternator today save the rotor. Had to dremel quite a few screws but now everything is nice and loose. I tried going down to home depot to pick up some replacement screws but they don't carry any like them from what the assistant told me. Any ideas where I can pick up some replacements?

I know what the regulator rectifier is as well as the alternator/stator. Taking apart things really helped the learning process. The plastic on the terminals coming from the stator has started chipping off.

Let me try to understand this again. Tomorrow what should I attempt to do to diagnose my charging system woes?

Also I forgot to mention I have the clymers manual. The brushes aren't the same length, they are still springy and haven't worn past the line.

[Soos]

If they aren't worn path the wear lines, you SHOULD be OK there.

I would seriously think about cleaning and applying some di-electric grease to ALL the connectors from the stator out.
And if you're gonna do that, why not ALL the connectors on the entire wiring harness.

You could be loosing a bit from just corrosion of the connectors throughout your wiring harness.


Are you running a stock headlight?
I tried running a higher wattage light once, and the battery CONSTANTLY kept loosing juice. I switched to stock, and the prob went away.

Any shorts in the system?
All turn signals working?


Good luck!!



l8r

[TwoTired]

DMM = Digital Multi Meter

You are going to need one you can trust.  It is unlikely you will be able find bad electrical components, or verify good ones with a visual inspection.  If you don't take electrical readings, then the alternative is to keep replacing parts till it works again.

Since you've taken things apart, you should see two copper slip rings on your rotor  (what the brushes contact).  You want to measure the resistance across those slip rings.  4.9 ohms is what you are looking to measure.

Cheers,

[Logite]

I measured the stator (or whatever the measurements between the 3 yellow cords going into the reg/rec are) and I got .7ish in between each. I'm getting 13v on a fully charged battery. It seems like the resistance is hard to measure unless I hold the pins in a still spot on the connectors which makes me think the connectors could use cleaning. I'll measure the rotor and update.   

[Logite]

Guys, what are the odds everything is screwed up? I haven't cleaned the carbon deposits off the rotor but I can't seem to get an accurate measurement on anything. Even with a $60 digital multimeter. I read the battery at 13v (with the bike off) but everything that requires resistance just isn't reading. My reg/rec won't give any readings at all besides continuity.

[Soos]

ughh....



Did that bike ACTUALLY start?
If it did it's a MIRACLE!!!
You NEED a new timing plate and at least a REALLY thorough cleaning for that spark advancer unit, I would go with one in better condition myself....

I know there are quite a few cb650 riders on this site with spare parts they would be willing to sell ya.

Where are you located at?

l8r

[TwoTired]

What does the face of your multimeter look like?

[Logite]

Here's my $60 toy.

[TwoTired]

Ok, but you covered up the labels where the leads plug in.

You have 5 function sections:
VAC = Volts Alternating Current
AAC = Amperes Alternating Current
VDC = Volts Direct Current
ADC = Amperes Direct Current
Ω  = Resitance

Your lowest resistance scale is 200 ohms.  I can't tell how many digits your display has (or read the brand and model number).
Anyway, select the 200 Ω scale and place the meter probe tip together.  Note the display value, as this is your lead resistance/measurement error.  You will subtract this reading from resistance measurement.

Since we expect to read 4.9 Ω or smaller this is only 2.5 % of full scale.  Makes me wonder what the accuracy spec is for your meter. (should be documented in the papers that came with it.

Anyway, it's what you have, so place the probe tips on the slip rings of the rotor, note the display, and subtract meter lead resistance.  Report your findings.

You could also go to radio shlock and buy a 10 or 5 ohm resistor.  You can check you meter's effectiveness by measuring this known resistance.  (To gain confidence in it's ability.  Or, prove it won't do the task required.)

cheers,

[Logite]

Thanks for that. Tested a 10 ohm resistor and got 10.2. I just tested the stator and got .9 across each terminal which leads me to believe it's got about .7 resistance. Seems a bit high. Will update with results of the other parts.

[Logite]

Did I miss something here? You have taken apart the ignition, the alternator is on the other side of the engine. BTW, you need a new ignition.

It was my first time taking it apart. Misread the instructions. All is well now.

How important is the ignition?

[scunny]

How important is the ignition?
your ignition lights the fire


plainly your bike runs but I'd be surprised if the advance unit(the rusty thing) is doing it's job.

[Logite]

I tested the rotor after cleaning it and it came up .6 ohms. I'm off to replace that as well as the reg/rectifier. Guess that was the problem. Thanks for all the help. Really appreciate it!