Found 10th Apr
I would call it the headlight but when I look it up headlight comes up with the high beam and what I am talking about is referred to as the side light.

Anyway, so I just have a little 125 and when I ride at night I have to go on country roads, they are no problem but there is no street lights. My front light is on but it remains pitch black ahead of me, ofcourse I can use my high beam but if there is a car coming the other way it is now dangerous for me to switch off my high beam - yet dangerous to keep it on at the same time. It was fine last week, and for 12 months before that.

I went out this morning and picked up a new bulb and changed it, obviously it's light outside so any change would be hard to see, but I have switched them over and back again countless times trying to see if one is brighter than the other and it doesn't appear to be. I will take another look when it gets dark tonight but is there anything else I could check in the meantime? Sadly I don't have anything to measure the W or Vs but if your suggestion includes this then go ahead and suggest it and I will have to find some way to do it

I guess more info could be that it has a very slight flicker, but it always has. And also it used to get a bit brighter when you rev. Again, it always has. I was told this is because at idle it uses the battery power but when revving it uses charging power - I say it used to because it no longer gets brighter when revving at all, which would kind of make me think of the alternator but no other electrics are having issues and the battery doesn't seem to be dying.

Tad more info, I cleaned my bike with a pressure washer like 5 days ago so I could of perhaps knocked something or got something wet/dirty (knocked dirt into somewhere?)

I'm really just at a loss for what to check so I appreciate all answers. To look at the front of the bike in the dark doesn't look dim, it's so strange to me how it looks fine but just isn't actually lighting anywhere.

26 Comments

My brothers bike done the same sort of thing. Have you changed any of the other bulbs. Because he had put a higher watt bulb in the brake light so some how was dimming the rest of the lights. But changed to the right watt and fixed all the rest of the lights. Hope this is some sort of help.

check your earth to that lamp too. A poor earth can severely affect the efficiency. A way to check is to run a separate wire from the earth on the light to the chassis.

Do you have a light adjustment knob? its usually within the dash area it allows up n down adjustment of the light. Not sure if a 125 will have it though.
Have you checked to see if water got into the light casing itself, this could have an effect also if the bulb in the correct position, if its facing the right way up.

Original Poster

Liam_188

My brothers bike done the same sort of thing. Have you changed any of the … My brothers bike done the same sort of thing. Have you changed any of the other bulbs. Because he had put a higher watt bulb in the brake light so some how was dimming the rest of the lights. But changed to the right watt and fixed all the rest of the lights. Hope this is some sort of help.


hmm nah haven't changed any bulbs for atleast 11months, I will check all the other bulbs are working properly though incase one has blown and is interfering

Exactly the same happened to my yzf r125 the problem was the earth to the lamp , had to change bulb and fuse and fix the wire .

Original Poster

mrty

check your earth to that lamp too. A poor earth can severely affect the … check your earth to that lamp too. A poor earth can severely affect the efficiency. A way to check is to run a separate wire from the earth on the light to the chassis.


I read about this wasn't sure what to do, I tried following the wire but it goes down to where I cant get to without taking some fairings off but I will try to have a good check today
rhinopaul

Do you have a light adjustment knob? its usually within the dash area it … Do you have a light adjustment knob? its usually within the dash area it allows up n down adjustment of the light. Not sure if a 125 will have it though.Have you checked to see if water got into the light casing itself, this could have an effect also if the bulb in the correct position, if its facing the right way up.

I think it does have an adjuster, though I think mine snapped when someone drove into me and is just fixed in position now but I will have a check lol I will fiddle with the bulb also when it gets dark

Original Poster

markymark81

Exactly the same happened to my yzf r125 the problem was the earth to the … Exactly the same happened to my yzf r125 the problem was the earth to the lamp , had to change bulb and fuse and fix the wire .


ah will definitely check out the earth then, will the fuse need changing even if it hasn't blown? they are really cheap so it's no problem, probably have some lying around anyway, just curious

murtgurge

ah will definitely check out the earth then, will the fuse need changing … ah will definitely check out the earth then, will the fuse need changing even if it hasn't blown? they are really cheap so it's no problem, probably have some lying around anyway, just curious


It is worth changing the fuse. Have a look in there, you could have some corrosion in there as well. Fairly sure as others have said it is a Bad earth.

If you can't follow the earth without dismantling the bike don't bother. Simply run a new earth from the lamp, finding somewhere in the chassis to connect to...Just don't join it to the earth for another light/circuit or you will have 2 defective circuits. You could, if you aren't worried about it not looking pretty, connect directly to the battery (short -term) this will prove/disprove the earth theory. Just make sure you cable tie away from moving or hot parts.

Original Poster

alright so I took the bike apart because I just got home and decided to rush into it before reading this, woops

anyway so the headlights (high beam and regular) are separate but then they merge pretty much instantly, so you have 2 green yellow white and black (I think) that goes in 1 end of a rubber tube and out the other end comes 1xgreen yellow white black and grey, unsure why 1 green seems to turn grey (?), if I unplug this connector a little further down my headlights and indicators don't turn on

anyway so then all of the wires are encased together so I can't follow individual wires but if I follow them all all of the earths (5 in total I think, think some are joined together) come out and are connected to the same part of the frame

I'm really not electrically inclined so I dont really know what I am doing other than fiddling so sorry for stupid questions, but how would I go about running a new earth? would it be as simple as snipping the current earth and extending it with some spare wire and connecting it to the frame?

I checked the earth connector to the actual bulb housing itself too and that seems ok

I took pictures of things I thought might be relevant but can't upload them at the moment


oh one last thing and this might be really stupid, but I find only 2 fuses and the main blue fuse, there is 2 red fuses, when I unplug 1 the electric start doesn't work, the other the indicators don't work - I don't understand where the one for the lights is hidden what is strange to me most is the 2 front lights being fed from the same thing and 1 of them is working as it should (high beam) and the other not - the earth for them is the same so would this rule out the bad earth?

Probably worth checking the battery is holding charge right as low voltage will mean dimmer lights.

What's the bike?
You should be able to get a wiring diagram online then it's just a case of checking the relevant wires and fuse(s) on the main loom.

Original Poster

joedastudd

Probably worth checking the battery is holding charge right as low … Probably worth checking the battery is holding charge right as low voltage will mean dimmer lights.What's the bike?You should be able to get a wiring diagram online then it's just a case of checking the relevant wires and fuse(s) on the main loom.


cbf 125 (2012)

the light doesn't look dim, and no other lights are affected (high beam, indicators, rear light, break light) just the very front - it's really weird to see in person (for me atleast), imagine shining a torch and you can see the torch is on but it remains pitch black infront of you, perhaps the person who suggested about the position of the light (could be facing too far up or down) was onto something .. but as I say it used to get brighter when revving but now it doesn't and it has been in a fixed position since the adjuster snapped in december so it really shouldn't have moved

but uhm, so I literally took the whole front of the bike because I figured while I'm half way I may as well try and fix the part that snapped when I was hit (the adjuster) so I took all the plastics off and got the lamp out completely. luckily the plastic was still there, though snapped, so it's currently glued and drying outside

it will go dark soon and then I can see if the bulb replacement and/or positioning has helped at all, while the glue is drying I will have a fiddle with the wires again and see if I can see anything

Original Poster

joedastudd

Probably worth checking the battery is holding charge right as low … Probably worth checking the battery is holding charge right as low voltage will mean dimmer lights.What's the bike?You should be able to get a wiring diagram online then it's just a case of checking the relevant wires and fuse(s) on the main loom.


oh also as for the battery, I used to have a ybr and the battery stopped holding charge on that to the point where the electric start wouldn't even work, but everything seems plenty powerful at the moment I can't see any sign of a power issue

Original Poster

Just put the bike back together, think the light is still the same but will see when dark

been a valuable experience though taking fairing off and what-not, and I'm glad the light adjuster is fixed properly - small victories

I checked the wire by cutting open the rubber sleeve around them all a little bit and the main beam and regular do join the grounds together. I opened it up properly to check the connection was ok and it did seem secure so I just put tape back around it and put it back in place

Original Poster

sadly it has gotten dark and the light remains useless

Have you checked that the regulator (alternator) is charging your battery properly, should be charging around 13.5v to 14.5v ? when engine running. You mentioned the light doesn't get brighter anymore which I'd say is a regulator issue. Regulators don't just pack up and die, they can regulate voltage to keep battery topped up or they can overcharge a battery when the voltage reading is over 14.5v etc. I don't think it's the battery if you don't have starting issues, I'm assuming your 125 is electric start ?
Edited by: "kovdarkangel" 10th Apr

Oh I didn't ask, has the brightness issue only started since the light doesn't get brighter when riding ?

Original Poster

kovdarkangel

Have you checked that the regulator (alternator) is charging your battery … Have you checked that the regulator (alternator) is charging your battery properly, should be charging around 13.5v to 14.5v ? when engine running. You mentioned the light doesn't get brighter anymore which I'd say is a regulator issue. Regulators don't just pack up and die, they can regulate voltage to keep battery topped up or they can overcharge a battery when the voltage reading is over 14.5v etc. I don't think it's the battery if you don't have starting issues, I'm assuming your 125 is electric start ?


haven't checked this as don't have a voltmeter uhm but yeah it's electric start and starts instantly everytime

kovdarkangel

Oh I didn't ask, has the brightness issue only started since the light … Oh I didn't ask, has the brightness issue only started since the light doesn't get brighter when riding ?


it's hard to pinpoint exactly, I ride mostly in the day but sometimes I will be out every night and other times just 1 night ride a week, I believe last time I was out at night was monday and everything was fine and then last night when I was riding home in the dark just could not see a thing without high beam, I don't really look out to see if it's getting brighter or not when revving so it's hard to accurately say whether or not it started at the same time as this issue I just assumed so

I hope it isn't the regulator cause I imagine it will cost some money to fix and maybe skill oO but do you think it is worth picking up some copper wire tomorrow and try adding a new ground to it? My only issue with that is that the current ground has this end on it and I don't really know how to attach a new wire to it without destroying it by prying it apart with pliers lol

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Original Poster

if it helps I just read this
'On the CBF, those lights are all powered directly off the alternator via the voltage regulator/rectifier'

this makes sense I guess because you can't use the headlights when the bike isn't running

You will need to check voltage first to rule out regulator/rectifier, regulators are about £30 quid onwards, however my advice is don't buy Chinese copies off eBay. It could be a loose wire somewhere between the regulator and battery or stator to regulator as you describe it as intermittent or it could be the regulator breaking down. I'm sure you will know someone who has a multimeter that can test the voltage at the battery for you. Everyone has a different opinion on what it could be so I would suggest reading this link to give you a better understanding on how your electrical system works. denniskirk.com/lea…cle

think you're just as well spending a few quid on a cheap multimeter to help you diagnose the problem.

maplin.co.uk/p/u…0ec

Original Poster

kovdarkangel

You will need to check voltage first to rule out regulator/rectifier, … You will need to check voltage first to rule out regulator/rectifier, regulators are about £30 quid onwards, however my advice is don't buy Chinese copies off eBay. It could be a loose wire somewhere between the regulator and battery or stator to regulator as you describe it as intermittent or it could be the regulator breaking down. I'm sure you will know someone who has a multimeter that can test the voltage at the battery for you. Everyone has a different opinion on what it could be so I would suggest reading this link to give you a better understanding on how your electrical system works. https://www.denniskirk.com/learn/how-to-diagnose-motorcycle


cheers will have a good read after in the morning

118luke

think you're just as well spending a few quid on a cheap multimeter to … think you're just as well spending a few quid on a cheap multimeter to help you diagnose the problem.http://www.maplin.co.uk/p/uni-t-ut33b-palm-size-digital-multimeter-n60ec


might be a silly question but do I have to buy the probes separate to this? It is out of stock locally I'd have to go ~30 miles but I have no problem going to get one, though on this topic do you happen to have a link to a site or video that would teach me how to use it properly and what the readings mean

kovdarkangel

You will need to check voltage first to rule out regulator/rectifier, … You will need to check voltage first to rule out regulator/rectifier, regulators are about £30 quid onwards, however my advice is don't buy Chinese copies off eBay. It could be a loose wire somewhere between the regulator and battery or stator to regulator as you describe it as intermittent or it could be the regulator breaking down. I'm sure you will know someone who has a multimeter that can test the voltage at the battery for you. Everyone has a different opinion on what it could be so I would suggest reading this link to give you a better understanding on how your electrical system works. https://www.denniskirk.com/learn/how-to-diagnose-motorcycle

118luke

think you're just as well spending a few quid on a cheap multimeter to … think you're just as well spending a few quid on a cheap multimeter to help you diagnose the problem.http://www.maplin.co.uk/p/uni-t-ut33b-palm-size-digital-multimeter-n60ec



The multimeter will come with the cables, use YouTube to search for testing a regulator.you can do the same for how to use a multimeter
Edited by: "kovdarkangel" 11th Apr

Original Poster

alright thanks for all the help so far

so battery when bike is off is at 13.3 (just been ridden)
when bike is revved it jumps up to ~14.68

I added a new ground and it made no difference

what I then did was, and I have no idea if this is correct, is put the red of the multimeter into the part of the bulb socket where the yellow wire goes, and the black to the grounding part of the bulb socket and it only read ~7 - I was expecting it to read 12 - and it does not go up when revved - to me this would mean a wire between the stator and the bulb needs replacing?

just did it again and it actually read 8 not 7 and jumps down to 3 or 4 when revved
Edited by: "murtgurge" 11th Apr

One thing you could do is use led bulbs, they use less energy so will shine brighter ;).

Original Poster

whew

Ok so I just follow the wire that takes the power to the bulb and cut away a lot of black tape so I could follow it properly and found a corroded part where it had been joined to a wire further up. Replaced that (sadly with green wire cause I don't want to go buy just for colour lol) and boom we are back in business.

Cheers for the help much appreciated to everyone and special thanks for the maplin multimeter link - I actually went in store and showed them the page on my phone as it was not on the shelf. They went in the back and got it out, said it had a different code and price for some reason but honoured the £5. Google actually says 65% price drop when you search it with maplin in the query so I guess it's a recent sale. Always happy to get a good deal and fill my empty toolbox up with useful stuff
Edited by: "murtgurge" 11th Apr
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