Yamaha MT125 2025 Model display only turning on if motor is on?

[u/_Melko_]

I just got this bike, almost new, and after 2 days of having it, the display will only turn on if the motor is running, and the motor indicator is lit up. I have chanrged the battery too. This is my first bike, so im a beginner at this kinda stuff, so i dont really know what to do here.

[u/Rapidlixard]

There is definitely some weird electrics going on here, engine light should turn off when the engine starts, if it stays on means theres an error code logged in the ECU/computer, the engine light most times is a very simple sensor not working or not connected properly so don't worry. A service centre can plug straight into the bike and check the code in a matter of minutes.

Also the dash should definitely turn on when you turn the key. So thats also something that needs to be looked at. Probably related to the first issue.

I would take it to a service centre. If it's almost new then it should be under warranty too so whatever it is should be covered! Just make sure you take it to an official yamaha dealer, so they can do the work under warranty.

Let us know how you get on!

[u/_Melko_ → u/Rapidlixard]

Thank you so much man :D (Update) i tried to test drive it, because i talked to the dealership and they told me that driving it would be fine. After abt 30 minutes of riding the display started bugging out and displaying 9 kph when i was driving 40, shortly after the bike shut off. I think the battery is dead, i charged it full, but it didnt hold, and the battery wont charge when driving. Its still under warranty like you said :] so im gonna take it back to the dealer to get it fixed up. Thank you all for helping me! Your so kind!

[u/Rapidlixard → u/_Melko_]

Your welcomeee! Yes that definitely sounds like the battery is dying, could be that it's not getting charged by the engine when you're riding, I suspect that there is something is up with the wiring that is causing all these issues. Also the dealer telling you that its fine to ride like that is a bit unprofessional... not that its unsafe, but there is clearly something wrong that could be fixed, just seems lazy to me from their part.

Btw quick question, you mentioned you changed the battery already before, was this done by you or at a dealer?

Once the issue is fixed I would ask the dealer if they could tell you what the issue was. I think its always a good idea to understand the issues. Even if your not fixing them yourself, you will feel more connected to the machine you're riding, and if you have issues in the future you will have some knowledge that might be able to help you :) I would also love to know haha just for my own curiousity xd

[u/_Melko_ → u/Rapidlixard]

Yess, it was me changing the battery, i asked my dad for help, (hes been doing this thing for a while. So he know how to charge it correctly.) And thank you so much for the tips :D i can try to keep yall updated when the bike comes back :)) thank you again :D

[u/_Melko_ → u/Rapidlixard]

(Update 2) The dealership told us to go buy a battery and change it ourselfs (because of the long wait) so we did, and it had the same problem of the display not turning on, but it was running! So we drove it to a mc practice area so i could get a feel of the bike. But after like 45 minutes the bike just died again, its the same problem as before, you can push start it, but the lights are flckering and the bike dies if your not touching the gas. I think the problem is, that the bike isnt charging the battery when riding the bike :[

[u/Rapidlixard → u/_Melko_]

Man that sucks :( I hope you can get reinbursed for the batteries they told you to buy. The bike clearly has an issue! Just throwing new batteries at it is not going to do anything. Im guessing when you mean wait time, you mean availability at their service centre and not wait time for parts. Have they run a diagnosis yet? That shouldnt take long at all.

Also one more question, since you mentioned you did all the battery changes yourself, did the bike have this issue before you changed battery for the first time?

[u/ambidextrousasswipe]

If this is done by design then some designer needs to find another job

[u/xtanol]

I'd check the ground connection on the frame, and the ground connection on your dashboard.

If either of those aren't properly connected, then your dash could be getting a false ground through some other grounded component once that part is switched on. Having your ground re-routing itself through something else that both has a solid metal connection to the frame and a cable connecting it to the ECU or dash, like most of your sensors, is also a nearly guaranteed way for that sensor to give false readings - which could explain the engine warning lights showing up.

I'd definitely check those two things before taking it to the shop to have the error codes read. Even though plugging in the reader takes two minutes, most shops will charge something like a $30-$100 fee for simply using the reader - along with a lot of shops having a minimum labour time (like 30-60 minutes) that they bill out.

[u/Rapidlixard → u/xtanol]

Yes, that is what i suspect too, however OP said the bike is under warranty so I recommend they do it through the main dealer. Dealer wont charge anything, its their responsibility to fix it

[u/DannoXYZ]

Does headlight turn on with key ON? Or only after engine has started?

There is diode under tank that may have corrosion on terminals. Unplug it, clean off terminals and plug back in.

[u/Pangtundure]

Maybe its some EU thing to save power, dosent happen with my 155

[u/Jelly_Round]

i don't understand, you want to have display on, whenever the motorcycle is turned off?

[u/Rapidlixard → u/Jelly_Round]

No I think they mean that when the ingition is on the screen stays off, which is definitely not the normal behaviour. When you turn the key the electrics turn on, fuel pump etc and normally this should turn on the screen/dash aswell.

[u/Jelly_Round → u/Jelly_Round]

What is with the downvotes if he posted like this

[u/SopmodTew → u/Jelly_Round]

They want the display on when the ignition is on....

[u/Tiranus58 → u/Jelly_Round]

Ignition

[u/aroundincircles]

RTFM? did you do it?

[u/Rapidlixard → u/aroundincircles]

RTFM? what does that mean?

[u/jayp0d → u/Rapidlixard]

Google the acronym “RTFM”!

[u/aroundincircles → u/Rapidlixard]

Read the fucking manual. I have no idea if this is normal behavior or not. On both my RE's the headlight does NOT come on until you start the engine (to save battery), every other bike I've owned the headlight comes on with the bike. On my classic, the headlight turns off when the bike turns off, the headlight on the Shotgun does not. I was confused by this.... Until I read the manual and it told me it was expected behavior.

[u/Deaddis]

Just a guess, but a low battery could be causing that, if you have a battery tender (or if you don't, buy one you will need one eventually!), hook it up and see if the screen turns on.

[u/AEDSazz → u/[deleted]]

Wrong on so many levels. Any and every killswitch on a bike can be used to turn it off without any issue, whether it’s the kickstand, the killswitch or the key.

In many countries, the standard practice during classes is actually to use the killswitch every single time as it helps riders have the reflex of using it in case of emergency.

Mechanically, it’s the exact same process no matter what way to turn off the bike you use, the key will only maintain the electrical on which is not a big deal.

[u/Jt07132829 → u/AEDSazz]

I can use my key? I thought the only way was the kill switch because they taught us in safety course lmao. I feel dumb now but at least I’m safe lol.

[u/AEDSazz → u/Jt07132829]

Yeah most safety courses teach killswitch which imo is the safest way to ensure muscle memory, and it’s also way easier of access, but I do use kickstand from time to time when I feel fancy coming up to a gas pump

But yeah your key definitely still turns your bike off lol

[u/Jt07132829 → u/AEDSazz]

Now I have to try it at least once.

[u/Rapidlixard → u/AEDSazz]

Yes, this

[u/Rapidlixard → u/[deleted]]

The bikes where you live are the same everywhere else, everyones got their way of turning off the engine, some use kill switch, some use the key or the kickstand. It all activates the same relay so it doesnt matter which one you use. As to which one is "safest" well thats debatable. Here in Spain we are taught to use the key because that turns off the electrics so we dont drain the battery. I just use the kickstand tho

[u/AEDSazz → u/[deleted]]

Your English comprehension is very limited so let me clear this up for you.

In case of an emergency, you must set this switch to X (off) as it’s the safest and quickest way to turn your bike off, yes.

Nowhere does it say on the manual that you should not use the switch outside of emergencies lmao.

“Use stairs in case of emergency” does not mean “never use the stairs outside of emergencies”

[u/Fillen02 → u/AEDSazz]

You mean I didn’t have to take the elevator all those times?!? /s

[u/NobodySpecific → u/[deleted]]

If the red switch was not meant to be used they would say that in the manual. If it caused any amount of harm whatsoever they would tell you and limit warranty coverage based on its use.

So please, show me ONE example of this being true. I will wait.

[u/arbpotatoes → u/[deleted]]

This means you can use it in an emergency, not that you should only use it in an emergency.

[u/NobodySpecific → u/[deleted]]

You should use this for an emergency does NOT mean "only for use in emergencies". It is not a fire extinguisher that can only be used once. It is not an AED with a battery that can only be used a small number of times. It is like stairs vs the elevator. You must use the stairs in an emergency. That does not mean you must take the elevator if there isn't an emergency.

[u/_Designer_Boner_ → u/[deleted]]

MT125 has two ignition switches?

[u/Equivalent_Camera_61 → u/[deleted]]

That's just wrong