Please help!! CBR125 | GTAMotorcycle.com

Please help!! CBR125

NinaTelle

New member
So, I purchased this bike in May just learned how to rid. I have had numerous problems with it and has become more of a headache than a leisure hobby.
First incident all the fuses blew, had to pull over and change a 10 fuse when i noticed the light on the speedometer, signals and breaks went out. It was fine, got to my destination and main fuse blew. I replaced all the fuses and then all of a sudden power went completely out.

Checked the battery and thought that may have been the culprit since it was not holding the charge. Replaced the battery yesterday and now will not start at all! It will struggle but will not turn over. A friend looked at it and said it could be the ECU. It is a 2008.

I really like this bike and to be honest i think i paid way too much for it hence i was a new rider and eager. All the tips or possible solutions would be so greatly appreciated!
 

GreyGhost

Well-known member
Site Supporter
Oy. Bad battery shouldn't blow fuses. Bad reg/rec might.

If it won't turn over, that is not an ECU issue. If it was turning over quickly and didn't start ECU would be a faint maybe. Did you charge the new battery?

Your first task is to figure out why the fuses went. Don't worry about the ECU until you have stable power.

@Brian P care to help this one out? He knows a hell of a lot more about that specific bike than I do.
 

Trials

Well-known member
So, I purchased this bike in May just learned how to rid. I have had numerous problems with it and has become more of a headache than a leisure hobby.
First incident all the fuses blew, had to pull over and change a 10 fuse when i noticed the light on the speedometer, signals and breaks went out. It was fine, got to my destination and main fuse blew. I replaced all the fuses and then all of a sudden power went completely out.

Checked the battery and thought that may have been the culprit since it was not holding the charge. Replaced the battery yesterday and now will not start at all! It will struggle but will not turn over. A friend looked at it and said it could be the ECU. It is a 2008.

I really like this bike and to be honest i think i paid way too much for it hence i was a new rider and eager. All the tips or possible solutions would be so greatly appreciated!
I bet the ECU is fine. Start with meter testing the stator and work down stream from there, do you know about electricity?
On second thought, maybe you should just bring it here and I'll fix the damn thing for you :|
 

TwistedKestrel

King of GTAM
Site Supporter
Some questions for you:

1. Are you sure that ALL or MOST of the fuses blew? Were the old fuses of the correct rating? The new fuses?

2. When you replaced the battery, did you charge the new battery first?

3. When you turn the ignition on the bike, does the FI light in the tachometer light up, and then go out?
 

Trials

Well-known member
The first thing you always do is google the term "carl salter" and your bike model:
Then download the free original factory service manual ;)
everything you could possibly need to know is in there memorize it :geek:
 

Brian P

Well-known member
Moderator
Site Supporter
Blown fuse means you need to ask the question WHY the fuse blew, because it didn't blow for no reason.

And, you need to identify specifically which fuses blew. I find it exceptionally unlikely that "all" the fuses would blow simultaneously ... that doesn't happen.

It is also exceptionally unlikely that the ECU is at fault for this.

Blown fuse generally means there is a short-circuit in the wiring, either due to a shorted/faulty component, or a fault in the wiring harness (typically, insulation rubbed through). *Which* fuse, helps you pin down what part of the circuit needs to be inspected.

If you don't know how electricity works, this is a job for someone who does.
 

Trials

Well-known member
Number one cause of fuses blowing is 🐭 mouse attack.
 

Brian P

Well-known member
Moderator
Site Supporter
And non-OEM tampering/accessories/"repairs". Seems to me that no one knows how to do electrical repairs properly.

And improperly routed wiring harnesses that lead to insulation being rubbed through because the harness chafes against a sharp edge. Sometimes said improper routing is due to improper repairs ... sometimes it's from the factory.
 

Trials

Well-known member
And non-OEM tampering/accessories/"repairs". Seems to me that no one knows how to do electrical repairs properly.

And improperly routed wiring harnesses that lead to insulation being rubbed through because the harness chafes against a sharp edge. Sometimes said improper routing is due to improper repairs ... sometimes it's from the factory.
Remember Radio Shack and Forrest Mims books? Doesn't exist any more.
 

mistersouthpaw

Well-known member
I bet the ECU is fine. Start with meter testing the stator and work down stream from there, do you know about electricity?
On second thought, maybe you should just bring it here and I'll fix the damn thing for you :|
Will you fix my bikes too ☺️🤙
 

Trials

Well-known member
Will you fix my bikes too ☺🤙
sure why not, I'm retired, nobody to ride with today so I have nothing better to do ;)
... I wouldn't just fix it for them anyway,
it has to be a learning experience for the owner or it's just a waste of a perfectly good broken motorcycle.
 

GVH

Well-known member
Stator or regrec problem is possible and yes fing mice. I put lots of free mouse food year round.
 

mistersouthpaw

Well-known member
sure why not, I'm retired, nobody to ride with today so I have nothing better to do ;)
... I wouldn't just fix it for them anyway,
it has to be a learning experience for the owner or it's just a waste of a perfectly good broken motorcycle.

The only problems I ever have are ones that I cause. I have this problem where I have to take apart everything I own
 

Trials

Well-known member
The only problems I ever have are ones that I cause. I have this problem where I have to take apart everything I own
Done that my entire life, it never ends.
The reward is in putting it back together better then you found it,
or at least to not **** it up.
 

Trials

Well-known member
Always nice to start by setting an oscilloscope to the 3 yellow or white wires that come out of the engine casing,
or at the very least resistance test between those 3 wires and ground to see if your 3-phase alternator is 100% good.
 

GreyGhost

Well-known member
Site Supporter
Always nice to start by setting an oscilloscope to the 3 yellow or white wires that come out of the engine casing,
or at the very least resistance test between those 3 wires and ground to see if your 3-phase alternator is 100% good.
You seem like a vintage test equipment kind of guy. Do you have a four channel scope? Obviously you could do one at a time, the question is just for interest.
 

Trials

Well-known member
You seem like a vintage test equipment kind of guy. Do you have a four channel scope? Obviously you could do one at a time, the question is just for interest.
little portable 2-channel, it's awesome.
way better then a VOM because you can see how clean the signal is.
 

Trials

Well-known member
Used it on these things mostly:
1591804110366.jpeg
 

bitzz

Well-known member
I use a multi meter.
With the bike running, check AC voltage across all the combinations of the three stator wires AB AC BC
Tells you everything you need to know about the stator function, you don't have to take anything apart, save the stator plug.

WHY would you need or want an oscilloscope? Kinda overkill, no? Clean signal? OFF a motorcycle stator? What does that even mean?
I might use an oscilloscope on the output of the rectifier, to look at the "ripple" of the output, where it matters.
It doesn't matter how "clean" the AC wave is, you have a rectifier to clean it up... and with the cheap/crappy rectifiers and stators found on motorcycles, the output will NEVER be "clean"
If you want to see "clean" output, look at the quad wound (basically 4 stators) Denso alternator found on GM police pack cars. Best I have ever seen, hardly any ripple... for the electronics found in police cars and the 120v/20amp AC plug in the back. Ripple screws with the real time clock in computers.
Motorcycle ignitions and lights don't really care about ripple.
 

GreyGhost

Well-known member
Site Supporter
I use a multi meter.
With the bike running, check AC voltage across all the combinations of the three stator wires AB AC BC
Tells you everything you need to know about the stator function, you don't have to take anything apart, save the stator plug.

WHY would you need or want an oscilloscope? Kinda overkill, no? Clean signal? OFF a motorcycle stator? What does that even mean?
I might use an oscilloscope on the output of the rectifier, to look at the "ripple" of the output, where it matters.
It doesn't matter how "clean" the AC wave is, you have a rectifier to clean it up... and with the cheap/crappy rectifiers and stators found on motorcycles, the output will NEVER be "clean"
If you want to see "clean" output, look at the quad wound (basically 4 stators) Denso alternator found on GM police pack cars. Best I have ever seen, hardly any ripple... for the electronics found in police cars and the 120v/20amp AC plug in the back. Ripple screws with the real time clock in computers.
Motorcycle ignitions and lights don't really care about ripple.
I'll admit, I have never scoped a stator, but how would it be at all noisy? It is from a rotating magnetic field, that should be as clean as it gets. Sure it may pick up a little noise but that should be orders of magnitude below the generated voltage. After the reg/rec all bets are off, there could be ton of junk there depending on the design.
 

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