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InaneCathode

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CB650 Not charging
« on: February 21, 2008, 08:45:34 PM »
I'm throwing out a line to you sohc experts on this problem,
Its with my brothers cb650, its not charging the battery and it's been like this since we got it. Heres the long and the short of it:
Stator tests good (from the plug 1.4 ohms between each yellow wire, no continuity to ground)
Rotor tests good (from the plug 1.5 ohms between the black and white wire, no continuity to ground)
R/R tests good (infinite resistance one way, no resistance the other)
Battery is old, but holds a charge

You start the bike and idle it, battery voltage sits at 11.5 volts and drops over time to 11 or lower. You rev it up to 5k with the high beam on (book says to do this, it should be 14.5 volts) and the battery voltage gets to 12 or 12.5 volts. The bike recieved a brand new r/r last year to solve the charging problem (old r/r tested bad i was told). The stator tests fine the rotor tests fine. Wtf? I poked the output plug from the r/r to see what its putting out, it's putting out 1 volt at 5k rpm, when you blip the throttle the r/r output bounces between .2 volts and 1 volt regularly, like its regulating, but WAY too low.

This problem is driving me nuts, i wish i could fix it but at this point i'm totally out of ideas. I dont get how its not charging when everything is tested good!

Help! I'm at wits end here!
Any other tests, parts, circuits i should be testing? Anyone in the colorado area who's an electrical genius?
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Offline bryanj

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Re: CB650 Not charging
« Reply #1 on: February 21, 2008, 09:07:01 PM »
OK quick test,
There are two wires that go to the wound rotor via brushes, diconnect these from the loom and feed power direct from the battery to the rotor.

If the charging voltage goes up the reg/rec is duff
If it dont the generator is duff
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Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

InaneCathode

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Re: CB650 Not charging
« Reply #2 on: February 21, 2008, 09:37:29 PM »
Ok i'll try that next time i get to the bike (next week) Is this like full fielding a car alternator?
If this determines the generator is duff, how do i find out which part in particular is bad?
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Offline TwoTired

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Re: CB650 Not charging
« Reply #3 on: February 21, 2008, 10:44:57 PM »
Quote from: InaneCathode on February 21, 2008, 08:45:34 PM
Rotor tests good (from the plug 1.5 ohms between the black and white wire, no continuity to ground)

Why do you think 1.5 ohms is good?
The rotor is the filed coil.  1.5 ohms means it draws about 8-9 amps from the system.
I believe that resistance should be about 7 ohms, drawing about 1.8-2 amps.

The insulation on the rotor winds seems to be problematic, breaks down and shorts the windings together.  This lowers the resistance reading significantly.

Got a spare rotor?

Cheers,
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

InaneCathode

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Re: CB650 Not charging
« Reply #4 on: February 21, 2008, 11:24:06 PM »
Dammit, more things to add to my mechanical OCD, I dont know why i thought 1.5 ohms is good, it isnt is it?
Thats another thing, i sure dont have a spare rotor! I'm on a ridiculously tight budget (fixing this bike for free for my brother, and i dont have any money myself) and everywhere i look alternator rotors are EXTREMELY expensive...
Is there a "Poor sohc bastard fund" or anyone in Denver, CO that can spare a good rotor for half an hour?  :D :D
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Offline TwoTired

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Re: CB650 Not charging
« Reply #5 on: February 22, 2008, 12:01:02 AM »
Well here is another happy thought.  ::)

The regulator usually can't handle high current draw from a shorted Field (rotor).  The over current overheats them and...well... maybe you get lucky?  :-\

Cheers,
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Soos

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Re: CB650 Not charging
« Reply #6 on: February 22, 2008, 04:13:59 AM »
The only thing I could suggest, is before swapping out parts, try cleaning all the electrical connections(sand them) and apply di-electric grease to ALL connections.

This may not fix your problem, but it could eliminate future ones.
I know on my '79 650 it never really would hold a charge when doing lots of in-town riding.
would HAVE to put a trickle charger on it WEEKLY, or it was dead.

After cleaning my entire wiring harness, and putting on di-electric grease, the battery has not had battery draining problems.
I hook it up once a month while riding, just to keep it topped off.
While not riding season, it gets hooked up until riding seasn starts again.

l8r
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InaneCathode

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Re: CB650 Not charging
« Reply #7 on: February 22, 2008, 08:58:11 AM »
Quote from: TwoTired on February 22, 2008, 12:01:02 AM
Well here is another happy thought.  ::)

The regulator usually can't handle high current draw from a shorted Field (rotor).  The over current overheats them and...well... maybe you get lucky?  :-\

Cheers,

Noooooooooooooooo!

I hope i'm lucky here, i dont want to have to be building r/rs for this stupid thing too :O
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Offline TwoTired

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Re: CB650 Not charging
« Reply #8 on: February 22, 2008, 09:23:41 AM »
Quote from: Soos on February 22, 2008, 04:13:59 AM
The only thing I could suggest, is before swapping out parts, try cleaning all the electrical connections(sand them) and apply di-electric grease to ALL connections.
While I completely agree that connector cleaning (I like those scotch-brite pads) is of major benefit in all these old bikes, cleaning serves to lower the circuit resistance and eliminate power waste as heat.  In this case, the rotor is already at too low resistance.  Lowering resistance further will increase the current draw, and put further strain on his (hopefully still good) regulator.  If his R/R is already burnt inside, it won't matter, though.

Cheers,
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

InaneCathode

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Re: CB650 Not charging
« Reply #9 on: February 22, 2008, 08:54:39 PM »
Tested the rotor today, tests no bueno. .5 ohms at the slip rings (considering the leads have about .3-.4 ohms in them themselves).
Bad rotor bad!
I'll need a good one before i continue :)

Anyone got one for cheap? Brother's tight on cash :O
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Offline bryanj

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Re: CB650 Not charging
« Reply #10 on: February 22, 2008, 09:25:04 PM »
Unfortunately that is the most common failure part and as such usable ones are rare
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Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

InaneCathode

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Re: CB650 Not charging
« Reply #11 on: February 22, 2008, 09:35:35 PM »
Doh!
Can they be rewrapped? I know one can do permanent magnet stators without too much trouble, can one do a rotor too?
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Offline Soos

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Re: CB650 Not charging
« Reply #12 on: February 22, 2008, 10:46:37 PM »
If you are interested... I do have a cb650 rotor.
PM me, I have one that was off a running bike('79), and one I can pull off a unknown condition motor(80/81).
The one I know is good ain't cheap though.
However, I will part with the unknown condition rotor for little or nothing over shipping as I have no idea if it is usable or not.

I do have a multimeter, and can do some tests on the unknown condition one I have, but am unsure how to check it properly.

l8r
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Just think to yourself what would Alowishus Devander Abercrombie do?
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(61mm)652cc 1979 cb650

Offline TwoTired

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Re: CB650 Not charging
« Reply #13 on: February 22, 2008, 11:45:41 PM »
Quote from: Soos on February 22, 2008, 10:46:37 PM
I do have a multimeter, and can do some tests on the unknown condition one I have, but am unsure how to check it properly.

Set your multimeter to the lowest resistance scale.
Place the two probe tips together and note the meter reading.  This is your measurement errors to subtract from future measurements.
Place a probe on each of the slip rings. 
Subtract your measurement error.

Cheers,
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Soos

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Re: CB650 Not charging
« Reply #14 on: February 23, 2008, 03:21:02 PM »
Quote from: TwoTired on February 22, 2008, 11:45:41 PM
Quote from: Soos on February 22, 2008, 10:46:37 PM
I do have a multimeter, and can do some tests on the unknown condition one I have, but am unsure how to check it properly.

Set your multimeter to the lowest resistance scale.
Place the two probe tips together and note the meter reading.  This is your measurement errors to subtract from future measurements.
Place a probe on each of the slip rings. 
Subtract your measurement error.

Cheers,



hahaha..... I knew that a multimeter in the bargain bin at checker autoparts couldn't be that good... but for 5.00, it served it's at the moment needed use.
There is only one setting on my multimeter I have for checking resistance.
And it is obviously not anywhere near sensitive enough to accurately read the resistance.
It works on the resistance I get from my spark plug boots, but this, no., and it shows 0-50 on the scale, and my boots came in at 5k resistance, at the 5 line.
 
I see a difference between the wires crossed vs. touching the slip rings, but i could not tell you how much exactly.
All 4 of the rotors I have test that way, even the ones on my running bikes.
I think I know someone I can borrow a better tester from this weekend.




l8r
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Just think to yourself what would Alowishus Devander Abercrombie do?
"Brix will be shat by your neighbors." - schwebel
(61mm)652cc 1979 cb650

Offline eurban

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Re: CB650 Not charging
« Reply #15 on: February 23, 2008, 03:55:33 PM »
IMHO don't bother with a used rotor for a 650.  These parts are pretty notorious for failure.  There are places to purchase reconditioned ones.  Perhaps Electrex and Oregon Motorcycle Parts. . . .

10 minutes later . . .Didn't see the rotors offered on Electrex or Oregon.  Ebaymotors had both new aftermarket and rebuilt oem ones.

« Last Edit: February 23, 2008, 04:07:00 PM by eurban »
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InaneCathode

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Re: CB650 Not charging
« Reply #16 on: February 23, 2008, 04:39:42 PM »
Quote from: Soos on February 23, 2008, 03:21:02 PM
Quote from: TwoTired on February 22, 2008, 11:45:41 PM
Quote from: Soos on February 22, 2008, 10:46:37 PM
I do have a multimeter, and can do some tests on the unknown condition one I have, but am unsure how to check it properly.

Set your multimeter to the lowest resistance scale.
Place the two probe tips together and note the meter reading.  This is your measurement errors to subtract from future measurements.
Place a probe on each of the slip rings. 
Subtract your measurement error.

Cheers,



hahaha..... I knew that a multimeter in the bargain bin at checker autoparts couldn't be that good... but for 5.00, it served it's at the moment needed use.
There is only one setting on my multimeter I have for checking resistance.
And it is obviously not anywhere near sensitive enough to accurately read the resistance.
It works on the resistance I get from my spark plug boots, but this, no., and it shows 0-50 on the scale, and my boots came in at 5k resistance, at the 5 line.
 
I see a difference between the wires crossed vs. touching the slip rings, but i could not tell you how much exactly.
All 4 of the rotors I have test that way, even the ones on my running bikes.
I think I know someone I can borrow a better tester from this weekend.




l8r

If they all test the same pretty much, i'll take the unknown one then :)
Might as well try, 160 bucks is steep for a new one!
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Offline Soos

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Re: CB650 Not charging
« Reply #17 on: February 23, 2008, 06:38:57 PM »
Ok, just got back from pickuping up the kids, and borrowing a good multimeter.

Not that it matters...

5.2 on the '79 rotor on my running bike, 45,000+ miles.
6.6 on my '81 with 11,000+ miles
6.6 on the unknown condition motor(PO said 10-12,000 miles)
5.5 on the spare sitting on my shelf.

Just touching the two wires together gives 0.2 resistance(ohms?)

l8r
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-=≡ Soos ≡=-
Just think to yourself what would Alowishus Devander Abercrombie do?
"Brix will be shat by your neighbors." - schwebel
(61mm)652cc 1979 cb650

InaneCathode

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Re: CB650 Not charging
« Reply #18 on: February 23, 2008, 06:51:16 PM »
Yup, the readout is in ohms.
Power equals voltage divided by resistance
Amps = Volts / Ohms
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Offline TwoTired

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Re: CB650 Not charging
« Reply #19 on: February 23, 2008, 09:57:14 PM »
If you have a choice, pick the one with the highest Ohm reading.

Cheers,
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

InaneCathode

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Re: CB650 Not charging
« Reply #20 on: February 23, 2008, 10:22:47 PM »
Nay, no choice in the matter on this one. Not that i'm complaining! You guys are awesome, seriously. Been on for less than a week and i've had this much help, simply amazing.
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Offline Demon67

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Re: CB650 Not charging
« Reply #21 on: February 24, 2008, 05:58:23 AM »
Inane Cathode
I have been told by mechanic I trust that a 650? Yamaha XS? uses a rotor that is tick thinner, 1/8 " maybe that fits the shaft and because Yamaha's system doesn't break down as much the rotors are cheaper and work like a champ. Now, have I actually done the swap, no have I seen the results, no but its something to  check into, and if it works for you, let me know as I went through hell trying to get a rotor for my 650.
Bill
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InaneCathode

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Re: CB650 Not charging
« Reply #22 on: February 26, 2008, 01:59:08 AM »
Got a rotor from the parts bike i just bought, stuck it on the running bike and voila! Charges! 14.2 volts at 5k rpm :)
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Offline TwoTired

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Re: CB650 Not charging
« Reply #23 on: February 26, 2008, 03:05:57 AM »
Congratulations!  Nice work.

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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

InaneCathode

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Re: CB650 Not charging
« Reply #24 on: February 27, 2008, 11:50:34 PM »
Yup, brother called me today just to tell me how awesome its running :)

One bike down, eight to go  :'(
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