Charging fault, strange!

[bikerestorer]

Hi People, havent posted for a while but i have a charging problem i cant sort out, i need help.

I have an XR 125 honda year of 08 model L6

Problem i have is battery wont charge and all parts are good? have changed generator, rectifier, battery, and ecu but still the battery discharges when you rev up??

I swapped the engine so new generator coils etc from a known good bike, from the same bike i also swapped the rectifier and battery and ecu as the doner bike was charging fine but still i have the problem, any ideas? i am allout of ideas.

Steve

[J.M.]

The cheaper thing to do would have been to buy a multimeter, because until you have one of those you're just going to be pissing in the wind.

Get hold of a multimeter. Measure voltage output directly from regulator at around 5k RPM and go from there.
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2004 R1 & 2018 XSR900

[bikerestorer]

Oh and if you use the front bake on tick over the neutral light gets brighter untill reved then it gets very dull < -- if reved while held on.

[Fizzer Thou]

It could so easily be a bad earth that you have missed.

With even a cheap £5 multimeter check the resistance between the negative side of the battery and any good bare metal part of frame or engine.There should be little or no ohms.

Without a good earth the return path to the battery will hamper the charging current.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[bikerestorer]

[lihp]

Your name is quite ironic
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covent.gardens: lihp is my most favourite member ever

[J.M.]

[bikerestorer]

[Fizzer Thou]

It is not worth guessing.Only by measuring if the earth is good can you be assured that there is no problem with the earthing on the bike.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[bikerestorer]

[bikerestorer]

[bikerestorer]

OK, as follows

Earth to frame 600mm away from poit of earth 0.00

static battery reading 11.83v

tick over erratic 12.1 to 12.9v

tick over with brake 12.21

rev with brake 11.95

sorry have no rev counter but estimate 5000 rpm

[bikerestorer]

I have just had the bike running on tick over with the meter on the battery and if i hold in the front brake lever and dont rev the engine it charges i would say normal?

ohh i wish i knew what tf it is thats wrong its getting me down now so much work and time put into this problem and nothing solved..;-(

[Fizzer Thou]

It sounds as though the operation of the brake light switch is creating an alternative earth route.

Now check the green/earth wire connection of the rectifier to the negative side of the battery and let us know the resistance reading.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[bikerestorer]

[bikerestorer]

[Fizzer Thou]

Quite often there is an earth wire that goes between the rectifier and the mounting point.But not in every case.I have not got one on my XR400 or KTM 450 as standard,but added one to each bike as I learnt from working on TZ350 race bikes that you cannot have enough earth straps.

Try adding a wire from the negative side of the battery to various points on the bike while checking the voltage across the battery.If the volts increase while using this flying lead,investigate that area for a broken earth wire.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[bikerestorer]

cheers for all your help, i shall try adding earths to the bike and will keep you all posted, as for now i am going off line have to get up early.

cheers see/ chat tomorrow thanks all.

steve

[tomh]

First of all try the simple stuff like changing the fuse in the starter solernoid (the return from the reg rec passes through here)

Check what voltage your getting on each yellow wiring going to the reg/rec, this will be reading in AC.

I would then be checking for any broken wires, put your meter on continuity test (the beeping one)

Disconnect the reg rec connector from the loom and check between red/white and the battery. Then check between green and the battery.

Disconnect the engine wires and check the continuity of each yellow wire to the reg/rec.

Also check the green wire from the engine to the battery.

If there continuity check what the resistance is.

[unitynotsocri...]

i'll put 10 % of my giro and go with Fizzer Thou on this,one green earth wire....somewhere............double check your control gear,genny ,loom and bits are correct.......then double check the wiring in the headlamp.............can be all to easy to shove the earths...greens...into each other except one of them greens is'nt a normal green ,as in to earth..........its a from earth.....as in the other side of the genny coils.....i.e. proper ground.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Pete.]

I had a similar problem on my bike last year. It checked out fine on a meter but one of the loom connections in the earth circuit was breaking down under load. Drove me crazy until I found it.

Go-over all your loom connectors and if that doesn't help run a separate earth wire from the rectifier to the battery and one to the engine. That will complete the return-circuit for charging and at least pinpoint the faulty circuit.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[bikerestorer]