YBR125 low charge rate, don't look like reg/rec

[whyber]

Ello. Bit of help?

'59 plate YBR125.

Been riding this on 15 mile commute across town for ages. Last week, started doing food delivery. Over course of the week, when riding home in the dark, found headlight gone very dull, not lighting up country lanes.

Went to turn bike over after finishing a shift on Sunday (warm innit), turnover slow, then went to just solenoid click.

Battery was 11.4 volts. When I put meter across battery and kick started the bike (I love that kick start on YBR125), it stayed at 11.something volts. I didn't rev it up (stupid), just measured it at idle.

I used to be a London despatch rider 15 years ago, did it for 8 years on and off, mostly on CB500s. I used to go through reg/recs when the weather was hot.

So, thinking it probably that, I just got one from Wemoto (£40 quid pattern, not OEM, which was £100), swapped it out. Charged the battery (it's a gel battery by umm "Fullbat"?). Was at 12.7v when I stuck it in.

Put meter across battery when running, the voltage drops to 12.1v when idling, gets to about 12.5v at 2500rpm, doesn't hit 13v until steady at 5000rpm. Over a few startups the battery is down to 12.4v.

I cleaned the pins on the old reg/rec, and it's doing exactly the same.

So all that ^^ does not seem right does it? Those voltages are too low.

What I reckon's been happening is - 15 mile commutes to my day job mean I do enough higher RPMs to keep battery reasonably charged. But since starting the food delivery in the evening the start/stop is draining it additionally - though TBH I'm probably doing more 5000+RPM then because roads are clear.

Or maybe battery is just munted - so one question is: if battery is failing, will the voltage showing while the engine is running be affected? I mean, show lower? If it is, then there's the possibility that a new battery will just sort it? Maybe cleaning the pin on the old reg/rec or using the new reg/rec fixed the problem and it's just the battery that's fooked?

If it's not, then it's charging system, but not the reg/rec. So corrosion on connectors (only one pin was a bit dull on the reg/rec I took out), some sodding short somewhere (I hate sodding wiring stuff grr), or (God no) stator. Right?

Penny for thoughts? To be honest, it's too bleeding hot to be out delivering stuff this week until I get acclimatised lol, but I need to get back to work.

Cheers for replies.
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Hot and tired

[Nobby the Bastard]

Normally if you see the voltage up above 13v at a decent engine speed then the stator is working and the battery is at fault.

I'd like to see nearer 14v at 5000k but that may simply be the battery sucking up everything the stator can throw at it and still discharging.

If it were the reg rec it would likely be massively over voltage (18-20v) or entirely disfunctional.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[stinkwheel]

Do some simple tests. You have a meter and you know where the reg rec attaches.

If I have the correct model, there are three white, a black and a red wire connecting intot he reg/rec block?

That being the case, unplug it and test for resistance between each pair of white wires, they should all show a similar and low resistance. Now test between each white and the black, they should all be open circuits. That's effectively tested your stator for shorts.

You can then do a dynamic test. Start the engine and with the reg rec unplugged, measure AC voltage between each pair of white wires, you should get a varying voltage probably somewhere between 12 and 30v depending on revs on each pair of whites.

If that's ok, your charging system is good. I'd still be expecting to see closer to 14v at the battery when the engine is revved with that type of charging system.

Sanity check, you haven't fitted extra powerful headlight bulbs or any electrical accessories that could be drawing down a lot of power?

There's only really one thing between the reg-rec and the battery which is the main fuse holder, may be worth checking that's in good order and corrosion free.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[whyber]

[whyber]

[stinkwheel]

The reason I asked is it's really common for people to fit a 55w bulb then wonder where all the power has gone (and why the plastic headlamp lens looks like a Salvador Dahli sculpture).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[whyber]

Arrgh.

Did ma tests. If we look at the plug for the reg/rec end on like this:

_____
|===|
|=_=|

(great drawing, huh?)

The white ones are the top three. Then when I do the resistance test across top left and top middle pins, I get 4.5 reading (with the dial set to 200). When I do the other pin combinations, including top left and top right, I get double, around 8.8.

I get no reading (my cheap multi meter just says "1") when I do each white pin to the black one.

When I do the AC check with the engine running, top left pin with top middle pin again has a different reading from the other ones, but they all came up between 12v and 30v. I didn't write down the readings.

So - would that imply bad connectors or something deeper? I can't get my damn front sprocket cover off, bolts are stuck, which means stator check might as well be a trip to a mechanic.

I rode the bike to work this morning on my 15 mile commute, kept its charge. I'm going to go do some food delivery this evening. Will check battery at end of shift (if it lasts that long!) and see how it held up.
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Hot and tired

[WD Forte]

Do the resistance tests again but properly

You need a good battery in your meter for resistance readings

Set the meter to its lowest resistance range
short the probes together to establish the resistance of the leads/probes
and note it.
Read between 1-2 then 1-3 then 2-3 and note it
Don't rush it, hold the probes in place for a few seconds.

Subtract the lead resistance from each reading for a more accurate figure
ideally you want see 1 ohm or less.

A '1' when reading from any white wire to ground is good
that mean its off the scale/too big to read
Anything else is suspect
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bikers smell of wee

[whyber]

[Nobby the Bastard]

I would say that one of your coils in the stator is shorted part way through.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[stinkwheel]

That seems problematic, suggesting there is a problem with your stator. I'm struggling to get my head around exactly what the problem would be because you'd expect an internal short to affect two phases or have continuity with ground. All is not as it should be and would warrant further inspection anyway.

The '09/10 models have a modern, 18 coil, 3-phase generator.
https://images.cmsnl.com/img/products/stator-assy_medium3D9H141012-01_2c81.jpg

The resistance readings seem on the high side too.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Nobby the Bastard]

Are the coils that make up a phase in parallel or series?

If a coil were to melt its wiring it would either go open circuit or most likely just reduce its resistance by bypassing half of the wire in the coil rather than leak to ground.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[WD Forte]

I wouldn't like to see 8 ohms on a stator resistance test,
that would concern me and as per Nobbys post, it may be a coil winding shorting internally to itself or insulation breaking down between phases.
It is around 14 years old as far as we know.

There's only so far you can go using a meter but in general
its a good rule of thumb method for indicating a stator's health.
Many times I've never had to go any deeper then that or put a scope on it.

The good news is:
I see new YBR125 EFI type stators on Ebay for £40 or so and they're a piece of piss to swap too.

Fowlers will take £330 off you for one

Generally they're Y or Star wound but could be Delta
there are pro and cons to each
____________________
bikers smell of wee

[Nobby the Bastard]

The only thing that confuses me about that is that the so called bad resistance coils are kicking the right sort of voltage.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[WD Forte]

[whyber]

Thanks for all the help folks.

Did about 3 hours of food delivery in town last night. Good bit of stopping and starting, did a fair bit of mileage, run home at the end of it is mostly high revs at speed on open roads.

This morning before setting off to my day job, I turned on the bike for 5 mins so the headlamp drained off surface charge and measured battery - was 12.4v.

Just got to my day job, 15 mile commute in, battery read 12.7v when I got off. I'll check it again before I ride off tonight.

Conclusion then for now - something's up innit. But it's sort of holding its own, managing to get up to a charge rate that is at least keeping me going. It's very possible it's been like this since I bought it off a young lad just before lockdown started (it basically did nothing but sit throughout lockdown). The battery is a gel one I put in, so it's supposed to be a bit more robust isn't it, but I honestly forget whether I put that in before or after lockdown, so might be older than I think.

I'm going to keep riding it for now, next time it craps out on me I'll sort it. Kickstarter will save, I'll never be more than 15 miles from home.

It's really annoying that I can't get the front sprocket cover off, of all things. Bastard stuck bolts, or I might take a look at the stator see if there's anything obvious visually. It's going to mean taking it to a mechanic to get it off godammit, which is why I'm holding off sorting the whole thing. Anyways, that's where I am.
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Hot and tired

[whyber]

Maybe you lot can sort an argument I'm having with a chap at work:

I'm using a powerbank I carry to top up my mobile phone while doing delivery.

Back in the day when I was a London courier on CB500s and the like, I just stuck a cigarette lighter socket with an inline fuse to the battery, and charged my old palmtop Windows CE device that way while I worked.

On my 125, I didn't want to do that, too many questions I am ignorant of concerning power draw and I basically couldn't be arsed to fit the thing anyway.

Chap at work reckons the power draw is nothing and why I don't I just do it as you can buy USB-C charging sockets for bikes off the shelf now yadda yadda.

When I google how much power gets drawn from 12v socket to charge a phone, I see can be up to 2 amps. Though I guess it can be somewhat lower, depending on what it's doing. On my little bike, even if it was healthy, what do we think of that? I'm unlikely to ever do it, as the power bank is a perfectly decent solution, but I'd like to settle the argument.

One thing I do know - had I fitted one last week when we were wrangling about it, that would have muddied the waters diagnosing this a bit.

Amusing story - back in the day when I first put that ciggy lighter socket on the CB500, it had a 3amp cable and no fuse. One time I plugged an electric tyre pump into it, which drew 10amps, melted the cable and set it on fire .
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Hot and tired

[stinkwheel]

Depends on the charger. 2A is a reasonably high current charger. Many of them are 1.2A.

I use one on my VFR but I only usually use it when the engine is running. I have on occasion charged something with it parked but I also have an onboard voltmeter and keep an eye on it. If it drops below 12.4, I stop.

I suppose a wee voltmeter on the dash would tell you a lot, maybe give you a little confidence? You can buy a cheap PCB mounted LCD voltmeter on ebay for less than a fiver. Stick it on somewhere and attach it to a switched live and earth.

I would be reluctant to use a USB charger on your bike in its current state as it's unpredictable how much charge is actually getting through and with a marginally more sophisticated FI and ignition system like yours has, if the battery is flat, you're screwed.

The really basic FI systems like the one fitted to honda scooters and earlier YBRs will self-excite and start on a flat battery as long as the injectors remain primed but you're is a slight step up from those (although is it a step up or a step backwards?).

I agree starting it on the kicker is a good plan and if you need it for work, hooking it to a maintainance charger overnight is probably a good plan.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[whyber]

Thanks for all the help folks, appreciated.
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Hot and tired

[whyber]

Hello folks, back again.

Riding the bike runs down the battery, unsurprisingly.

I kept riding doing food delivery, kickstarting it. Eventually it wouldn't even kickstart and I was broke down.

Woo hoo, get me. The battery, which is a gel one, was down to less than 10v but you know what? Charged up again. Have not tried it in anger since, but gel batteries are better at being run right down, aren't they?

Aaanyway - here's a photo of my stator, having finally got the stuck bolts on the front sprocket cover off (bastid). I think this is fooked, no? Coil burnt out. Is it a straight swap out then I need to do?

Cheers for replies.
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Hot and tired

[stinkwheel]

Mmm. Crispy.

There are places that will rewind them but then you'll be without the bike while it's being done. So replacing it seems the sensible option.

Looks pretty straightforwards to change out. Looks like the stator and sensor unbolt then bolt the new one in. You'll probably want some threebond (or other RTV) on the rubber grommet. You may also need to unwrap part of the loom to run the wires up to where they need to be and wrap it back in again. Doesn't look like there's any wiggle/adjustment on the timing pickup but if there is, you may need to set the clearance between the pickup and the trigger on the rotor.

Test the output as soon as you start it up. While the stator is cooked and definitely why your bike isn't charging, a bad stator can make a reg/rec fail and a bad reg/rec can make a stator fail.

No motorcycle batteries like being run all the way down so try not to, that's a job for a deep cycle battery. Keep it as full as you can. If you're going to run total loss with overnight charging for a long time, it might even be worth getting the biggest deep cycle battery you can fit in the battery box and just run that with the reg/rec disconnected so you don't damage your new fancy battery. Small deep cycle batteries are relatively cheap as I recall.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jeffyjeff]

Probably not a bad idea to change the oil when you swap out the stator, if you were not planning to do so anyway. Oil cools the stator, and the charred coil may have overheated the oil, or contaminated it with charred debris. Considering the YBR has only a nominal filter screen under the clutch cover, there is no "proper" filter to rid contaminants from the oil. When I changed the burnt stator on my PC800, it became immediately apparent why the oil was getting black on the dipstick.
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History shows again and again how nature points out the folly of men - BOC

[whyber]

Yeah I've been looking at deep cycle batteries to go with an electric outboard trolling motor that I've bought for my small inflatable boat. Traditional lead acid are by far the cheapest, but you can't run them down low for all the normal reasons, AGM better but gel is the way to go if you're not going all out expense on LiPo (nope! lol).

On a marine deep cycle you can run a gel one down to 20% of... whatever unit of indicated charge they were referring to, I forget.

It's a bit of a moot point as I had to buy a new (lead acid) Yuasa one from Halfords anyway to get me home the night I broke down. No profit for me that night, but did encounter several kind and helpful people as I struggled through it.

I have here in my mortal hands a Haynes manual that's describing the stator removal and installation to no great degree of detail, but should be OK. I have some marine sealant RTV for my boat that will probably be good enough.

Thanks for help man .
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Hot and tired

[whyber]