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My bikes not well... YBR 125 help please.


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Hi ( again )

Sorry bit long.

Ive had to sign up under a new name as I cant recall my old one Very Happy

Wondering if some of you good people can give me some advice here please?

So I've got a 2009 ybr125 EFI version that I have had from new. Had been reg. serviced and looked after for a 125.

So a few months ago the odd time I would come out and go to do an electric start and the ignition light would dim. Turn it off and on again for a sec ( I work in IT ) and next time it would work fine. Used to get the odd cut out when at light and pull away. Again restarted on the button

Move on a few weeks and this time it didnt start so used the kick start and though it was the battery. 9 years old so replaced it. Been fine till now.

I came out very early this morning and turned on the ignition. Everything went out like no battery was in there. Desperate to get to work I ended up bumping it. Apart from the EML light staying on a bit longer and the rev counter going to zero then flickering for 10 secs it drove in fine. As I was half awake thought I must have done something stupid.

Roll on this afternoon and I come out of work. The bike is dead, again like no battery. Have no choice but to kick start it. The rev counter starts jumping everywhere or zero. I try and drive off as I will look at it when I get home asap. Goes 300 yards then cuts out.

Spend next 2 hours with AA who thinks its the battery but as his own admission I dont know anything about bikes. Hes trying to charge my battery with a booster pack ( Im sure this will over charge it? ) Then hes now doing it direct from his van and booster for 10 mins.

Long story short again. Bike may start from kickstart or with booster applied but does run for more than a few feet.

Its now home but dead. But every so often springs to full life ( not started ) lights, flashers, horn everything works. But touch the electric start and its as dead as a dodo again even if you turn it off and on again. Also the EML light is flashing code 39 for a injector issue but Im not sure if this is getting caused by the rectifier or battery?

Really could do with some brains please?

Cheers. Crying or Very sad

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Guest Richzx6r

I'd start with getting a new battery that you know is fully charged, what the aa guy did could have possibly affected the reg rec as they aren't made for handling the kind of force that boosting from a booster pack and using his van at the same time would have produced.

As for the injector code I'd wait till you get a new battery, if it fires up clear all codes then run the code reader again see if the same code appears then if it does replace it with an injector of known quality to check it

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Ok so this gets stranger ( I thought this happened earlier too but so so busy messing about with the AA man I wasnt sure.)

A few others have mentioned this over various pages.

So hour ago bike was dead, dead, dead ( batt showed 12.5 v whilst off ) the only signs of life were if you attached the trickle charger to the battery. Then it worked as normal but the EML light kept flashing a fuel injector fault code.

So I have just gone out to the bike and turned the key. All alive but EML FI code keeps flashing tried this 3 times and does same. Have run hand all round the electrics no change. But this time I tried the kick start. EML light goes off as it should. Everything works like the batteries in prime shape! I try flashers, horn even heated grips..perfect. Head lamp stays bright no matter if revving or no. Perfect. I shook the bike hard side to side. Bounced it. ran hand round all electrics. Absolutley no issues. No rev flicker, nowt. Whilst running batt at 12.5/13v all the time even when turning things off and on.

Did this same sequence 3 times......perfect each time and same results.

( now that must have been the equivilant of the bump start this morning. )

So this time I turn on the ignition again and its ready in the same state. BUT the second I hit the electric starter the electric go out?

Of and on again, the dash lights flicker as well and headlights then it sort of looks ready to start again. Press the electric start and all dask goes out but I can hear a tapping from under the petrol tank for 8 or 9 secs.

So odd

Right so in the time it took to write the above Ive gone out to the bike again ( its almost like it resets itself if left for a bit, ready to work if you use the kick starter method again ) and its flickering on the EML light/Neutral lights. The second I hit the electric start its like no battery and all dead again. I can still hear a few of these faint clicks.

So I put my voltmeter on the terminals and its at 0 volts

Tried on a diff battery and theres 10 volts or so there so its not the meter. Go back to the bike and theres 12.5v there again. Bizarre. Then I realised the bike was off still. I turn the ignition on and hey presto 0v on the meter. I can do this several times.

Its almost like once you try it on the electric start it nicks all the voltage/battery and the bike remains dead until its had a chance to clear whatever is going on.

Anyone any clues please?

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as I say its deffo looking like something to do with this electric starter or seems to be?

never had any issues before.

even when the bikr is just switched on and looks ready to be kick started ( no flickering dash lights ) soon as I hit that electric starter. dead or flickering...

Does it draw massive amounts from the regulator/rectifier at this point? and that kills something temporarily?

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Sounds like your regulator/rectifier is fried. These can throw up some weird faults. Sometimes with an intermittent problem the wires from reg/rec will show telltales signs of melting - follow the wires to the connector blocks, pull them apart and check carefully, cos you could replace the battery and reg/rec and still have a problem.

Also just double check the connections on the starter are clean and tight.

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was going to write..

cant work this out then

when the bike is 'ready' eg all dash lights fully bright again and eml light comes on then goes off as it should everything seems to work perfect. I havent taken it in the road yet but but gave it loads off bouncing and side to side in case something was lose.

the only time it goes wrong is when you have it in a 'ready' state and hit the electric starter. its dead after that or near as dammit.

however you suggestion about the starter could be it?

if hitting the electric start earths it somehow ( that could be the clicking ) and keeps earthing it ( hence the batteries dead after that ) and left for half hour what ever it is is no longer engaged and hence the bike goes back to normal and can work with a kick start. Might explain all the weird lights very early this morning and the rev counter going wild if whatever it was is still stuck then freed?

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Before you do anything else check the battery EARTH wire . That's the black one . Start at the battery and follow it down to where it is connected . Usually it's bolted to the engine or the frame . To be sure of a good connection , unbolt it and clean the terminal with sandpaper . Re connect and give it a go . You could inspect and do the same to all other battery connections while you're at it. With any fault finding process , always start with the cheapest and simplest things first .

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as I say the odd thing is unless you touch that electric starter first it appears to be the bike works exactly as it should.

but I will have a look in the daylight.



That sounds typical of a loose battery lead . Ok until you put any load on it .

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I agree with checking the main earth but also have you ever fully charged the new battery with a trickle charger? The volts showing 12.5 doesn't mean it's fully charged. Low voltage will do all sorts of strange things.

If the charge is low hitting the starter will cause the battery voltage to collapse.

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Thanks for replies.

batteries all tight. cleaned up in addition by the AA man and rechecked last night by me. I've only got a basic voltmeter so 12.5 is my average reading.

ok go out to the bike this morning and it looks dead on the dash when I turn on the ignition.

again I hear the faint 'clicking'

clicking stops and the dash springs back to life, kickstart it, runs perfect.

so thinking ( and I have very very basic knowledge of starters here ) that when I push the electric start it throws the solonoid? which engages the teeth which spin on the bike to start the engine.

so the 'reseting' is either a spring or something else disengaing the starter solonoid again then the bikes fine.

whilst engaged or pressing the electric start to try and engage it its either earthing out somewhere and hence bike appearing dead or as on my bike you cant get the starter to fire if the bikes running its doing something along those lines?

Going to have a look around the starter now but dont really know how to test the starters good

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when its in its 'ready' state as I call it eg ignition on all lights bright and not running, I can turn on the heated grips full blast, flashers, brake lights all at the same at the voltage doesnt fluctuate at all. tiniest dim on the daytime running lights whilst the flasher goes but that it so again believe the battery and connections to it are good.

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ok so the bikes in its ready to go mode so I start it on its kick starter, perfect. Go for a quick drive to get some petrol.

As I could see my chain was a bit loose ( i knew about this ) I thought I would pop in to the bike shop and get a quote to replace.

I tell him about this issue. He says battery. Told him its fairly new. So he does a voltage test seems fine. I tell him not to restart using the electric starter. We start it again via KS and it runs fine, he checks voltage he seems happy. I mention I think its something to do with the switch again. Turn off bike and try to start via switch. Bike dead. A minute later the bikes 'ready' again eg all the dash is bright. He puts battery booster pack straight onto starter motor. Engine starts fine. Do again. engine starts fine. So we dont think its the starter motor either.

Turn off bike to discuss chain.

I went back to bike and which is 'ready' forget and press electric starter button and dash starts flickering out. KS it and it runs enough to get me home but its erratic and rev counter all over the place.

So look at battery and terminal again. all is clean. look at positive to starter motor, its all in its rubber housing, nice any shiny.

However whenever, in this 'unready' state when I turn the bike on the battery voltage goes to zero, when bike ignition is off it at just under 12 volts if the engines not running.

Hellllllp :-(


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It controls how the battery is charged.

It converts AC to DC for the electric start.

If the electric start works off the power pack but not off the bike's system, then reg/rec is the most likely culprit if you've already ruled out loose/dirty/corroded connections on battery and starter.

I would have thought the garage guy had any savvy he would have checked it

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so had my old battery ( original 2009 swapped earlier this year ) and had on trickle charge all day.

swapped it over, bike wouldnt start just the clicking. Measured voltage 9v. so expected.

went to 'new' battery, off bike, and says 12.5v. did as someone suggested and added a halagen and dab each end on a terminal. battery 0v

did the same test on the old battery. it lit the bulb, just about and dropped to 2.5v

conclusion. then new battery is a duffer. thanks all.

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