Yzf R125 electrical help required

[Silicon]

A couple of years ago my son, in his wisdom, thought I was talking through my backside when I told him he needed to check his oil level at least weekly.

His bike, the above mentioned YZF R125, began to give indications it was about to have a hissy fit but he still insisted it was fine. That is until I got a phone call saying “my bike just died”.

Oh it had died ok. The piston had seized and pretty much exploded. The engine would still turn over but you can imagine the noise.

When we opened it up the skirts had all broken off and the top of the piston was just bouncing around in the barrel. New top end for sure and maybe more.

The engine came out and we decided that while we had it out we might as well strip the whole thing and make it nice. The project has come along nicely and the bike is looking very tidy.

When we were stripping it I game the job of stripping the electrical wiring from the frame to my son. Yes he knows better. I asked him to label the connections but he reckoned he could remember them all. I won’t make that mistake again.

So here I am a handy guy with a bitter hate for vehicle electrics, actually any electrics for that matter. I just cannot get my head around them and I’ve trained as an engineer. The problem isn’t major but I’m not getting any front left indicator action. I have one spare connector which I assumed was the indicator connection but when I’ve put the multimeter on it I get a stable 1.2v when I switch the indicator on. Everything else is working as intended except for this damned indicator (however I haven’t got the fan to work after getting the engine up to temp, I have tested this connection too but there’s no signal there.

So in short no front left indicator.

Connection I thought was correct is showing a stable 1.2v.

The other items using that same shaped connector are all working (except maybe the fan)

Help, please.

Edited August 15, 2020 by Silicon

[WD-40]

There's a manual. Not sure if it's the correct year for your bike. Have a look at the colour diagram at the end. You don't have to understand it, just follow the colours. The left indicator is a two pin connector with a brown wire and a black wire. http://www.automotivespartsshop.com/file-download/YAMAHA-YZF-R125-SERVICE-MANUAL.pdf

[Silicon]

I knew there would be a common sense solution to finding the fault. I’ll check the wire colours and let you know what I find.

[Guest Swagman]

Have you tried testing the fan with the wire from the indicator and vice versed.

[Silicon]

Hi Swagman,

Yes I’ve tried that. I’m going to have to test the temperature sensor at some point too. At a pinch I may just have to splice into the rear indicator and run some new wires if I can’t find the problem. I’m definitely not paying a shop to do the work.

[WD-40]

Did you get the indicator working? What year is the bike? What colour are the wires on the connector that you don't know where it goes?