Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: Mike_Berkshire on February 04, 2025, 01:04:09 PM

Title: Testing Alternator etc
Post by: Mike_Berkshire on February 04, 2025, 01:04:09 PM: Hi all, can anyone point me in the direction of a testing approach for CB550 charging circuit. I have tested for voltage across the battery when the bike is running at about 3,500 rpm and Im getting just a smidge over 12 volts which is presumably the standing voltage across the battery. I have replaced the rectifier but not regulator; everything else is as I got the bike. I have had a trawl through hints and tips and the only thing I can find is a link which now leads to a game download site as opposed to a testing regime. Cheers, Mike
Title: Re: Testing Alternator etc
Post by: Sesman on February 04, 2025, 02:49:01 PM: Mike.

Have you tried the CB550 manual in alladins cave?
Title: Re: Testing Alternator etc
Post by: Sesman on February 04, 2025, 03:10:40 PM: Page 93 to 97. Start with the rectifier input and output voltages, remembering that the input is AC and output is DC . For the â€˜inputâ€™ check between each phase and phase to earth.

My money is on a failed rectifier🤞
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 04, 2025, 03:12:59 PM: Thanks - ill give that a go
Title: Re: Testing Alternator etc
Post by: Sesman on February 04, 2025, 03:16:34 PM: Page 97 shows the â€˜static, off the bike methodâ€™ of testing the rectifier.
Title: Re: Testing Alternator etc
Post by: ozzybud on February 04, 2025, 03:34:28 PM: First check that the field coil is getting energized with the key on engine off. Take the left honda nameplate off.
With the key on the three screws should become magnetic. Check with any steel object. The fiels coil is fed by 3 yellow wires #6 in diagram.
Title: Re: Testing Alternator etc
Post by: Bryanj on February 04, 2025, 05:28:30 PM: There is also a bulletin on the 3 phase charging circuit operation in either Ashs dropbox or Alladins cave.
I would say 95% of charging problems are bad connections
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 04, 2025, 07:14:21 PM: Completely agree Bryan, normally poor dirty connections will cause voltage problems.
Another factor that is now starting to happen on these old bikes (50+ years) is the copper winding insulation (stator & field coils) are starting to degrade and fail. Most Kawasaki stators that I have refurbished in the past have failed a high voltage test to the frame, not because of electrical use, the insulation material is becoming less soft and flexible.
Title: Re: Testing Alternator etc
Post by: deltarider on February 04, 2025, 07:23:38 PM: Quote from: Bryanj on February 04, 2025, 05:28:30 PM
[...]
I would say 95% of charging problems are bad connections
So... also check for chafed wires.
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 04, 2025, 08:44:05 PM: Thanks for all the pointers. I will do some investigating at the weekend.
Title: Re: Testing Alternator etc
Post by: Bryanj on February 05, 2025, 12:16:30 AM: All you need is a decent multimeter that gives accurate low resistance readings
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 05, 2025, 03:42:04 PM: A good quality multi-meter is ideal, image attached. Most stator windings that I measure (end to end are around 0.5 ohms) but the test voltage test is only around 6volts.
Back in the day, did you have an high volt coil winding insulation tester (test point end of a winding to the stator frame) ? If you did, what was the test voltage on the machine ?
Title: Re: Testing Alternator etc
Post by: ST1100 on February 05, 2025, 03:52:04 PM: Quote from: BigAl (Alan) on February 05, 2025, 03:42:04 PM
Back in the day, did you have an high volt coil winding insulation tester (test point end of a winding to the stator frame) ? If you did, what was the test voltage on the machine ?
What was the operating voltage of that device?
The "Mega-ohmmeters" regular avail are operating with 250-500-1000V... might be a bit harsh on coils designed for like 60V... but the poof of smoke eases spotting the leak... ;)
Title: Re: Testing Alternator etc
Post by: Bryanj on February 05, 2025, 04:23:43 PM: I just used the Honda Sanwa SP10D (analogue meter) for resistance and a megger for insulation, wiring disconnected of course
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 05, 2025, 04:30:20 PM: Currently using my insulation tester 250v/500v/1000 (as image) which I think (250v) is a bit high...I'm guessing that the workshop machines where rated at 100v/125v?
When the stators come back from the rewinders they measure perfectly (scale 250v) value 200M/ohm's
Memories...When I was a lad at Tech, I was told...It's not a 'mega' it's an insulation tested...as a 'hoover' is a vacuum cleaner
Title: Testing Alternator etc
Post by: SteveD CB500K0 on February 05, 2025, 04:59:06 PM: Iâ€™ve got one of them Al

The AVO - not the modern digi-thing.

Sent from my iPhone using Tapatalk
Title: Re: Testing Alternator etc
Post by: Bryanj on February 05, 2025, 05:26:19 PM: Very true Al but Megger was the name on the one i had, but then 17th edition outlawed mine as it used a fraction less of a milliamp to test than was writted down!
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 05, 2025, 05:28:41 PM: They are a nice bit of kit...much better than the old wind-up 'Megger' - insulation tester as image...no batteries required!
Title: Re: Testing Alternator etc
Post by: Sesman on February 06, 2025, 12:12:09 AM: Meggaâ€¦.Excellent tool for measuring the insulation resistance of apprentices.
Title: Re: Testing Alternator etc
Post by: ST1100 on February 06, 2025, 07:56:02 AM: Quote from: BigAl (Alan) on February 05, 2025, 05:28:41 PM
They are a nice bit of kit...much better than the old wind-up 'Megger' - insulation tester as image...no batteries required!
The first HIOKI we had ran on a 9V block battery... loved that analogue thing, so easy to read...
Those digital displays (SODIAL VC60B+) always take a moment to decipher...
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 06, 2025, 09:22:21 AM: Quote from: ozzybud on February 04, 2025, 03:34:28 PM
First check that the field coil is getting energized with the key on engine off. Take the left honda nameplate off.
With the key on the three screws should become magnetic. Check with any steel object. The fiels coil is fed by 3 yellow wires #6 in diagram.
I had a spare 5 mins last night so nipped into the shed test if the screws were magnetised when ignition on; they were not. I am assuming it is the three inner screws you mean; the ones that sit in the counterbored holes?
Title: Re: Testing Alternator etc
Post by: Bryanj on February 06, 2025, 09:50:12 AM: Try putting a jumper wire from battery positive to the white regulator wire and see if they magnetize then, if yes reg or wiring if not wiring or coil
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 06, 2025, 09:39:44 PM: Cheers Bryan. Iâ€™m capable of that and will try and find a few mins to do that tomorrow.
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 08, 2025, 08:01:36 PM: Rather than fit a jumper cable fro the battery I probed the white wire at the regulator. It was showing 12 volts but not magnetism at the alternator screws. Iâ€™m polishing the wheel hubs now to get ready for wheel rebuild so once thatâ€™s done Iâ€™ll get back on the alternator.
Title: Re: Testing Alternator etc
Post by: Oddjob on February 09, 2025, 12:47:23 AM: Iâ€™d check there is still 12v on the white cable where it joins the field coil. If there isnâ€™t then thereâ€™s your problem. If there is then maybe the field coil has failed for some reason.
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 09, 2025, 12:11:49 PM: Just out of interest, what is the field coil resistance on a CB550?...I know the CB750 is around 7.5ohms (4.4ohms on the CB750A)
Title: Re: Testing Alternator etc
Post by: Bryanj on February 09, 2025, 01:44:15 PM: Cany remember off hand but download the proper manual from alladibs cave
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 15, 2025, 12:38:07 PM: I have tried to access the manual in Alladins cave but for some reason I can open it or download it; I will try again later as our internet connection is a bit flaky and it might just be a connectivity issue. In the meantime, although this is all a bit of a dark art to me, I have tested that the white wire terminal out of the regulator to the field coil is live; it is. The voltage at the earth connection of the field coil is 12 volts too. The resistance of the stator coil windings are between 0.6 Ohm and 0.8 Ohm so there is continuity there but differing resistance. Despite the fact the filed coil is being energised there is no magnetism in the three bolts that hold it to the alternator casing; could it be that stainless bolts have replaced the originals and would that matter? I cant think of what to try next without the manual so I will keep trying to access it or find it elsewhere.

Are the stator coil winding resistances OK?
Title: Re: Testing Alternator etc
Post by: Mike_Berkshire on February 15, 2025, 01:47:56 PM: Has anyone used one fo the replacement combined regulator rectifiers like DS sell in this charging circuit and if so what thoughts? An upgrade to a more modern integrated unit could be a good upgrade?
Title: Re: Testing Alternator etc
Post by: Bryanj on February 15, 2025, 03:06:07 PM: Disconnect the white wire at reg and check resistance to ground, with power off obviously. The white and green wires have connectors behind the sprocket cover that can fail
Title: Re: Testing Alternator etc
Post by: BigAl (Alan) on February 15, 2025, 03:19:14 PM: According to the Clymer manual readings as below (CB500F/550F) -
Field coil (white wire to green wire) the reading should be 4.6 to 5.0 ohms.
Stator windings (3 x yellow wires) readings between each yellow wire 0.35 +/- 10%
Obtaining an accurate reading (0hms) of the stator windings can be problematic due to dirty contacts and cheaper end resistance meters.
Ask Steve if you can borrow his AVO meter