Author Topic: CB 500 weird alternator readings  (Read 4516 times)

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Offline bryanj

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Re: CB 500 weird alternator readings
« Reply #25 on: October 07, 2018, 12:27:09 pm »
For information the 750 and 500 generators have exactly the same type of parts but  different physical sizes, regulator and rectifier are identical
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).

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Offline Alex

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Re: CB 500 weird alternator readings
« Reply #26 on: October 08, 2018, 07:36:46 am »
No, that's exactly right. Not sure what a picture would prove.
The battery "-" has to be securely connected to the frame and engine cases for things to work, of course. Usually that's via a heavy cable to one of the engine hanger bolts, with the frame paint scraped off where the bolt and cable terminal touch it. You can use an external tooth lockwasher - these pierce the paint or powdercoat for a good electrical connection - but those are not easy to find in the large size needed.

Thanks!
Double checked allt the ground connections and they seem good when testing continuity with my multimeter.
Sanded off some extra paint to be extra sure. :)

Offline Alex

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Re: CB 500 weird alternator readings
« Reply #27 on: October 08, 2018, 07:38:03 am »
Alex - take the following voltage readings when you get back to your bike:

From R/R BLACK to battery POS (this measures voltage drop through the harness). This should be well under 1.0v, much closer to 0.5v.
Voltage reading at LOCK with engine running at idle and 5,000 RPMs.
Voltage directly at battery for same conditions as taken for LOCK.

Somewhere in your installation, the R/R is not generating a charge because its losing reference to the battery's condition. That's my opinion and position on your situation.

Alright!
Never tried that!
Out of town at the moment, but I'll check as soon as I'm back adn I'll let you know how it went!

Offline Alex

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Re: CB 500 weird alternator readings
« Reply #28 on: October 14, 2018, 08:19:59 am »
Alex - take the following voltage readings when you get back to your bike:

From R/R BLACK to battery POS (this measures voltage drop through the harness). This should be well under 1.0v, much closer to 0.5v.
Voltage reading at LOCK with engine running at idle and 5,000 RPMs.
Voltage directly at battery for same conditions as taken for LOCK.

Somewhere in your installation, the R/R is not generating a charge because its losing reference to the battery's condition. That's my opinion and position on your situation.

OK!

R/R BLACK —> Battery POS = ca 203mV

Reading at LOCK:
Idle = 12,7V
5000 rpm = 13,2V

Reading at battery:
Idle = 12,94V
5000 rpm = 13,5V

Seems to me that the numbers are good?



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Offline calj737

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Re: CB 500 weird alternator readings
« Reply #29 on: October 14, 2018, 08:35:53 am »
Those numbers seem fine, but the max volts is a bit low. What headlight and other aftermarket accessories are you running? Perhaps these are pulling too much current for your system.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Alex

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Re: CB 500 weird alternator readings
« Reply #30 on: October 15, 2018, 04:53:13 am »
Those numbers seem fine, but the max volts is a bit low. What headlight and other aftermarket accessories are you running? Perhaps these are pulling too much current for your system.

I'm using these:
Headlight: Original headlight
Turnsignals: FRONT - m.blaze discs / BACK - m.blaze pins
Rear/Brakelight: Shin Yo Shorty Led
License plate light: Shin Yo License Plate Led
Speedo: MMB Mechanic Speedo w. indicators.

So, everything is basically LED, except the headlight.
No extra accessories like USB-port, warm grips, etc.

Offline TwoTired

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Re: CB 500 weird alternator readings
« Reply #31 on: October 15, 2018, 08:06:05 am »
Stock coils and points?
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 Alex

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Re: CB 500 weird alternator readings
« Reply #32 on: October 15, 2018, 09:33:04 am »

Offline TwoTired

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Re: CB 500 weird alternator readings
« Reply #33 on: October 15, 2018, 11:06:54 am »
The numbers seem good to me.  What is missing is voltage trend info while revving 4000-5000 RPM.  If it eventually stabilizes at 13.8 -ish, I wouldn't complain.

It also kinda matters if the lighting is on or off, as that can impact how hard the alternator has to work to maintain electrical happiness at any RPM.

Cheers,
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 Alex

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Re: CB 500 weird alternator readings
« Reply #34 on: October 20, 2018, 02:50:46 am »
The numbers seem good to me.  What is missing is voltage trend info while revving 4000-5000 RPM.  If it eventually stabilizes at 13.8 -ish, I wouldn't complain.

It also kinda matters if the lighting is on or off, as that can impact how hard the alternator has to work to maintain electrical happiness at any RPM.

Cheers,

Yeah, weirdly enought, these are the best numbers I’ve ever received.
But I haven’t had it out for a longer test ride yet. I’ll have to see how it responds when it gets a bit warm, since it died on me last time I took it for a longer test ride.

I’ll try to get the 4-5k trend info this Sunday!

Well, the light turns on when hitting the ignition start. I may have to install a head light switch!


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Offline remcoseegers

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Re: CB 500 weird alternator readings
« Reply #35 on: October 25, 2019, 11:24:28 am »
Old thread but I am facing exactly the same, measuring 1.2 Ohm on the yellow wires. Did you ever get to solve it? How?

Thanks!

Offline maxheadflow

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Re: CB 500 weird alternator readings
« Reply #36 on: October 25, 2019, 05:47:51 pm »
It's the connectors.