Please help me guys!

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

Hi all, I will introduce myself after this post.
Basically I'm having issues with my 2004 Honda xr 125 charging. I've purchased a brand new battery and it's still dead after a long ride. I've tested the regulator/rectifier and that comes back as okay, all within .2 ohms of each other and continuity test is coming back okay.
I've tested the stator and that's coming back okay I think.
It not shorting to earth and looks to be in good shape.
I'm lost with this. I'm a HGV mechanic so I'm pretty clued up with engines but this has baffled me.
Does anyone have any advice on more tests I can do or possible causes I can chase up?
Many thanks in advance.
Mike

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Have a read through this and follow all the steps, will give you the answer.

bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

apply what you know about trucks and their charging systems....you have a multimeter??

get a wiring diagram.......anything coming out of the yellow wires?? ac??
____________________
nuts about bikes

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

Nice one sickpup much appreciated.
Bike nut, truck are totally different, not only are they 24v they only have 1 alternator wire. I have a multi meter but can find a diagram. Can't really find a lot on this engine.
Thanks for the help so far guys, I will repor back after work.
Thanks again.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Raffles · World Chat Champion Joined: 14 Apr 2009 Karma :

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Reg/rec testing is tricky. You can check the resistance across it, but this doesn't tell you if diodes have failed. There is a way of checking diodes if your multimeter is capable, google will eventually show you how.

If you've got charge coming out of the alternator, and no charge showing at the battery, expect reg/rec failure. They die from time to time.

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

In fairness, I work on things between 7.5 and 22 tons so they are all 24v.
I've searched Google for the last 2 weeks to find a decent thread on it but have come up with nothing.
Thanks for the diagram mate, I will have a look when I'm home, I'm eager to try the step by step testing that sickpup posted.
I wasn't quite expecting this kind of response, so thanks a lot. 😊

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Ever worked on 24V FFR 90amp set ups? Always useful to know if I have problems with mine.

WD Forte · World Chat Champion Joined: 17 Jun 2010 Karma :

This came up as the first result of a google search for
'Honda XR125 wiring diagram' and it looks pretty typical to me.
https://www.cmelectronica.com.ar/wiring-diagram/imagenes/honda-xr125_color.jpg
I've worked on 24V trucks and bikes are simple in comparison
especially a Honda 125 single
fault finding is easy
The stator should have little to no resistance between yellow phase wires
and very high/open between any phase to ground
anything in between is suspect
Check the 3 way plug carrying the stator to regulator wires as they've been known to burn
out.

The regulator can be diode checked with a meter but regulation can only be checked when running
Check the battery standing voltage, ideally 12.65V ish and start the bike.
The voltage should go up to and regulate around 14V pretty quickly with no load/lights
unless the battery is very discharged when it may take a little longer as it recovers.

If it looks ok but drops when you turn the lights on, check the rating of the headlamp bulb
Some eejit may have stuck a 100W in there which will consume all the limited stator output.
____________________
bikers smell of wee

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

It's a little bike, with a little generator, and a little battery.. is it really not charging..... or could it simply be it is just not getting enough charge?

Common on these sort of little bikes, for them to be run with the head-lamp constantly 'on'.. either cos that's wot chap on CBT said to do, or 'cos that's how the factory wired them, without a switch to turn them 'off'... and even pitiful 35w bulb, will take lions share of what charge the geny makes... (Even more if some-one has tried fitting a higher wattage one, cos so dull... worth a check!)

Next up; starter drain; Honda decided to fit an electric boot to the old CG engne in that bike in the early 00's... it never had a wonderful electrical system to start with, and they didn't uprate it much to cope with the power draw of a big electric starter motor (Big being relative here!)

IF the bikes not the 'best' starter, then prolonged button to get it to catch, is likely to suck more juice from the battery than the engine can put back in very soon.

Worth checking the rest of the motor over; changing oil, tickling tappets, changing the spark-plug, looking at how you use the choke, and what your 'warm-up' routine is.... then how, and how long the motor gets run between start-ups...

Hint; typical newby habit, especially by more mature, car drvng owners, is to not rev the things out; to 'short shift' using tall gears and low revs, thinking that its not 'thrashing' the thng and is good for ecconomy; in fact, such riding is making the motor labour, so isn't so good for economy, while it's denyng yourself engine response and making more work for you making extra up-shift, and hence more unnecessary down-shifts, which often conspire to make braking and stopping more 'jerky' and less precice than needs be....

BUT more pertinently.... that little generator is probably only rated at something like 90W.. (watts not Amps!) 'max' and it'll only deliver that, at stated crank revs, probably near peak-torque, about 9,ooo rpm.

SO... if you near dead the battey to get the thing to start n the button, not the boot... with the head-lamp still switched 'on' soon as you turn the key... and take longer than needs be to get it alight....there wont be much juice left n the battery when you start riding... short-shifting, never going over 6K rpm, you wont be gettig the full 90W out the genny, you'll like get less than half that 'on average', between running as you stop at junctions and stuff, motor turning at idle speed.... head-lamp sucking 35w of the 45 or so it's delivering, side-lamp, tail-lamp, stop-lamp, indicators, all taking more, so that over a typical journey, equipment takes more from the battery than the genny puts in.. result... flattery.... after a few rides.... with NO actual real 'fault in the bikes generator, regulator or battery... it's just not got that much 'spare' to play with, and is just unable t deliver as much as is asked of it.

So, before getting all eager with the multi-meter and wiring diagram... that's where I would start, and make SURE there's actually something that needs 'fixing'!
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

The thing is, I can have the bike running for an hour or so on tick over and as soon as I switch off its barely got the charge to click the starter relay.
As far as riding it goes it's only used every few weeks, I have a car that I drive and also I'm not interested in speed on this thing, my car does that just fine for me.
It's more of a let your hair down kind of toy.
I will take the starter off and have a look at that aswell while I'm at it.
I've rebuilt it in the last month (problem has be going for longer) so I know the condition of the gears and shafts, crank and top end. Oil is new.
I will get to the bottom of this. Thanks again guys.
Your all helping in your own way Wink

jjdugen · World Chat Champion Joined: 03 Jun 2011 Karma :

As Teff says, tickover is just discharging the battery, you need to be revving to get any appreciable charge.
____________________
The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

Tick-over will barely keep the side & tail lamp lit, let alone put back the Amp hours you'll have drained to get it started.

Go give it a good thrashing; use some revs, not so many gears, and blow the cob-webs out of the thing!
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

Val · World Chat Champion Joined: 03 Nov 2012 Karma :

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

Hi again all.
Right, i had a slightly productive couple of days.
I have found a slightly broken wire on the live feed to/from the regulator.
its now charging at around 13.9v which sounds about enough.
What is weird though is that the battery only last for about 7 seconds of pressing the start button after that it just dies off and the solenoid starts clicking. the battery isn't flat though, i had a friend round today with potentially the same engine just a Chinese one so most of his bits fitted mine for testing purposes. anyway, my battery on his bike worked perfectly, turning the engine over for ages and not going flat, so i put his battery in my bike, surprise surprise, runs out of steam after 7 seconds.
Anyone know what could cause this?

i have done many of the tests you guys have told me and they all come back pretty good.
The step by step one was a bit hit and miss with my bike and a friends giving figures that wernt on the test and it telling me i have a dodgey live from regulator the starter solenoid which is in perfect order.

Thanks in advance

mentalboy · World Chat Champion Joined: 05 May 2012 Karma :

Shinigami · World Chat Champion Joined: 14 Feb 2012 Karma :

hit it with a brick
____________________
Current: ~~Honda City Fly CLR125~~ ~~2003 Honda CB600F Hornet~~ 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

I've repaired the wire already with crimp connectors and heat shrink.
I can't work out what's up with it. I'm thinking a wire shorting out but I would have though I would have got a burnt out wore or something.

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

crimp... CRIMP... C-R-I-M-P! Now go fix it properly! HOW many electrical faults are chitty crimp-chimp connections... fn-has-ifnar mutter, pet-hate, bludy crimp-connectors, whats wrong with solder these days for gods sake! Good enuff f'Romans! Roman Solder was the ency of the world-it-waz! Chimp-Connectors! Humph!

Oh well.. so there was a fault..... or more...

7 second battery.....

When you bought this 'ere new battery... silly question time, BUT... did it come 'dry'.. no acid in it? Many don't.. you have to add the acid.. and the cheaper ones of e-bay often don't include the acid-pack, you have to buy it seperate; the battery comes 'Dry-Charged' though, so it will sort of work, BUT less you have properly filled it with acid, and let the acid settle, before charging on trickle off the bike... letting it settle and checking the electolyte level,... across all cells.... before fitting the fill plugs.... then they wont hold a full compiment of charge....

Next up; 'deep-discharge-deterioration'... starter motors draw a higher current than the battery can 'normally' sustain; why they are often fuel rated, say 45Ah and 90A 'Cold-Cranking'.. the Cold-Cranking rating is an indication of how much they can be 'deep-cycled, sort of 'over-driven', sucked of charge quicker than they can really handle.. but only briefly.

In 4x4-ing, common issue, when they start fitting big winches; things can have 3Hp electric motors on them; about 2.25Kw, or at 12v, P=IV, let me do the sums... err... 2,250/12 = 190A approx... and a big car battery, can just about deliver that, through very heavy cable... just not for very long, or very often.. so the chaps that go quarry-bashing or doing these challenge events, where they seem to go out of thier way to get a couple of tons of metal stuck in a muddy hole, find that after only a few recoveries, thier battery is toast, and not only wont it pull a rotten Disco out of a hole, it'll struggle to turn over its AGA engine.... because, forced ito 'deep-cycle' for too long, too often, the electrolyte and the coating on the lead plates starts to break down, and the charge holding capacity, starts to reduce, as does its deep-cycle capability; consequently, serious wincher's will buy expensive 'Deep-Cycle' batteries, that have a much higher peak current rating, and deep-cycle capacity, and more serious ones still go 24v to halve the amps...

However, interesting as that may be.... same issue afflicts 'little' bike batteries... which don't tend to have the same 'life' as even ordinary car batteries to start with.... I bought a new battery for my Honda Civic about five years ago... it might need a new one this winter, 3-5 years s about the expected 'life' of the things; Bike batteries? About half that. Maybe two years; I certainly reckon I'm doing allright if they last more than that.

AND they can be toasted SO easily... I had a gummed up starter motor on the 750, year before last; changed the battery, and thing still struggled to turn the starter unless fully charged! Stripped the starter, changed the brushes, cleaned some gunk out the gears, put it back on... and... battery was toast.. as the 'problem' migrates.. tired starter, drains tired battery, new battery spins up tired starter, but kills itself in the process; fix starter, and now tired battery struggles to turn starter... "But its a brand new battery!... Must be the solenoid".. which is where it starts getting infuriating....

BUT, upshot is, my advice is start fresh; don't assume that because something is 'new' that its 'good'.

Don't know what relay is on that bike; but some of the little honda relays are quite 'nice' and can be disassembled, to reveal a big, thick, brass contractor plate that can be filed flat to get the pits out of it and clean the corrosion off, so it actually passes full compliment of current, rather than arcing.... start there, and have a look if it screws together, and if you can strip and clean it; if not, replacements are only about a tenner, swap it out to be sure.

Then look at the starter motor; I think that Chinky clone CG starters are only about £25 on e-bay, where a new-brush set for the Honda starter is about £12+ postage from Dave-Silvers... your call, but I strip the Honda ones and fit new brushes.... you could get away with just a strip and a clean; old brush dust and corrosion on the contacts often makes them lazy; but I've had a few, where even though the carbon-brush hasn't been worn so far it's only making intermittent contact, high current has over-heated the braid wire to them, and made it 'thin' so they cant carry the amps they try suck.. so worthy precautionary replacement while you have the damn thing in bits...

THEN, with known good solenoid, and known good starter, and having made sure that the earth strap between engine and battery is good, and has good clean metal to make contact too... (also worth cleaning up the bosses on and for the starter for same reason), THN buy a brand-new battery, and follow the instructions as to filling it, charging it, and letting the electrolyte settle and level, before you bolt it to the bike...

Then you know that all three major components are 'good' and that the problem shouldn't migrate, one duff component afflicting another... at least for a fair few years.

But, I would hazard, that its the whole system that's a it tired not just the battery, and one bit has been afflicting the other, and will continue to do so to greater or lesser degree unless you tackle the lot, in one go.

Non-Charging due to loose feed wire from the regulator? A 'problem' but as to the 7-second starter issue; I don't think its likely to be particularly contributory, other than, letting battery go lower, and so be more deeply cycled each time you tried starting it.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

Crimps are fine when done properly, there is a sthinkwheel thread somewhere proving crimps are stronger that the surrounding wire.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

The battery is a Varta one which came with the battery acid in tubes you put in your self. I followed the instructions and its worked fine.
the issue is the battery is working perfect on other bike yet the other bikes battery's are not working on mine.
I even swapped the starter in case mine was draining to much power and it was still the same.
I've tried unplugging different things whilst turning it over and to no success.
The starter solenoid was new not so long ago but like you say it could be knackered and not sending enough power to the starter, but if i put a live straight to the starter terminal its still exactly the same.
I really don't understand this bike.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Disconnect the live to the starter. Voltage check on live side of relay then voltage check on other side with starter button depressed, what are the readings?

Once running does the bike seem underpowered?

M1k3n3a1 · Derestricted Danger Joined: 24 Sep 2015 Karma :

Battery voltage is 12.90
Battery to relay 12.16
Really to starter 11.71 after 10 seconds.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :