CBR125R no ignition lights

[VFR1200rider]

Hi all, sorry for my first post being in the workshop rather than introducing myself.

I bought my missus a CBR125 a few years ago, after she got the biking bug being on the back of one of mine, she had no issues with it in the 3 or so years of having it, partly because it was on the floor more than being ridden, I had used it for work numerous times and never found any issues.

Her son passed his CBT and she had agreed to sell him the bike, but let him use it before he had paid a penny towards it.

Within a week he said that a work colleague said the valve clearances needed done as the engine was rattling, I checked myself when he said this and the engine sounded fine for a 125.

He told me that the bike hadn't been run properly, so he had to "rag it" from time to time, again it's a 125, so I agree after letting it warm up properly.

One day I got home from work to find him trying to bump start it on a small hill, which he said was the first time he tried to bumpstart it.

I got off my bike and the first thing I noticed was he was trying to bump start it with no ignition lights on, but the rev counter was sat at 7k rpm, even though the key was in the On position.

So far I've replaced the battery and the starter relay, when I changed the starter relay the fuel pump coughed and spluttered a few times but still no ignition lights. If I bridge the starter relay the bike will start, but the voltage stays around 12v and turning on the indicator cuts the engine.

So I'm looking for advice on where next to start, part of me is thinking maybe the CDI is fried, but I'm open to suggestions.

It's a 2014 CBR125R with around 12k miles

[stinkwheel]

Have they been interfering with the wiring?

Knowing 17 year old boys, they are magnets for uninformed bullshit about ways of "derestricting" 125s so it'll do 100mph all day long. They then proceed to fuck about with things they have no idea about based on little more than hearsay from a mate at work/college/down the pub. Or I suppose in this day and age, social media.

Including but not limited to drilling holes where holes aren't meant to be, adding miscillaneous humours to the fuel and engine oil and cutting/rearranging wiring.

Assuming it's not been fucked about with as described above, what you describe sounds like it could be an earth fault. Earths on small Hondas are green wires. Check for damage and corrosion anywhere they attach to the frame or engine. Also have a good look at any high movement areas of wiring such as where it passes the headstock and anywhere bodywork attaches for signs of worn/trapped/abraded wiring. Also if it's been left sat in a garage for a protracted period, check for mouse nests and damage under the seat and tank and behind body panels. Mice love to chew wire insulation and connector blocks.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[VFR1200rider]

I thought an earth fault would be an intermittent fault, not bike is fine one day then nothing the next?

His biker mechanic mate, (that told him about the engine needing stripped becuase of the imaginary rattle), "helped" him try to fix it by saying it needed a new ignition barrel, from a CBF 125, and they worked on it all day and still couldn't get it running. Her son did say that night when I got home that "someone had tried to steal it at some point, as the wires had all been cut"

Someone, definitely not him or his mate, had cut the plug from the end of the ignition wire, (where it joins the loom), then reattached a couple of spade connectors. I've reattached the spades properly and still no ignition lights, but if I bridge the starter relay it all lights up and the bike does cut off when I turn the key off.

Most of the front and side fairings have been off and I've not noticed any bare or damaged wires from rodents, but I'll have a check for earth faults, even though I didn't break it, so I don't see why I should fix it when he keeps saying he's going to take it to a garage the next time he gets paid, the next time, the next time etc.

[stinkwheel]

Well, if the engine runs, the CDI is probably ok.

I suggested earth fault because you said it cuts out when an indicator is turned on which suggests to me that the ignition is being earthed via that.

From the new info, it's probably the case that wires are crossed somewhere, something or things are connected up wrong. Having a workshop manual is going to be the key to success so you know what connects to where. Then it'll be a case of methodically working it through.

A wiring diagram is daunting to look at. I find it helps to break it down into systems and chase those through one at a time. So broadly, you have the starter system which clearly isn't working, the ignition system which is mostly working but has some faults such as the rev counted being on the blink and being connected into the flashers for some reason, the charging system which also isn't working but shouldn't stop it running and the lighting system which is also on the blink.

The manual should have a breakdown of each system and where it's supposed to be connected.

Check your fuses.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.