Which fuel pump for 2015 Yamaha ybr 125cc?

[Samon_x]

Hi, I'm having some issues with my bikes fuel pump but when looking at a replacement I cannot seem to find one for the correct year. My bike isn't the 'custom' model and the pumps for sale are for years 07-14, is it possible that these pumps will fit and function fine?

Thanks for any help

[Nobby the Bastard]

Fowlers say there is no 2015 YBR so you probably have the 2014.

Are you sure it's knackered? They ain't cheap...


https://www.fowlersparts.co.uk/parts/5452406/ybr125ed-2014-51d3-europe-bluish-white-cocktail-1/fuel-tank

pt. no. 32
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[WD Forte]

Fowlers £325 for pukka Yammie one
or Ebay £48 for an oriental alternative with all the bits and bobs

https://www.ebay.co.uk/itm/324009260171?
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bikers smell of wee

[MCN]

[Kawasaki Jimbo]

[stinkwheel]

If it was me, for that kind of money, I'd probably make up a fuel pump delete plate on the tank with a spigot and re-plumb it to run an external facet solid state pump. Maybe with a small car cartridge fuel filter if I could find somewhere to put it. Probably looking at around £100-150 to do all that and it would never need looking at again.
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“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.

[WD Forte]

the original pump assembly also carries the fuel level sender
so a delete plate would stop that function or you'd need to
include that too.
plus you'd need some over pressure return not just one pipe

To much faffery for me, I'd probably take a chance on el cheapo
it looks like it comes with all the associated filters n shit too.

while it was out of the tank I'd see if the old pump just needed new brushes or perhaps a new valve/s or regulator which is probably a spring loaded non return valve with a make'break switch attached to it.

Of course, I'd whip it out before spending any dosh and want to ensure it really is the pump failing and not just a bad electrical connection.
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bikers smell of wee

[Samon_x]

Hi and thanks for the responses. Just to clarify a bit, my bike has been having electrical faults for a while before I've narrowed it down to the fuel pump. I'm still not certain it is the pump that needs replacing as I'm a noob.

It started with the battery being weak and running low a few times meaning I've had to push start it more than once. After charging it it still had issues after not riding for a few weeks . Took it out for a 20 mile ride and on returning back to my garage it wouldn't start up again so I push started it and noticed when revving the engine the rev needle was dancing around depsite me holding steady revs. My brother helped me diagnose with a multimeter that the battery was dead and also not charging when the bike was running, which meant crap battery and a charging issue. Looking inside the engine case the stator was spotless. So I replaced the reg rec with a wemoto one to see if that would fix it. When testing the new reg reg in the bike with the old battery (new battery was in the post) it was charging but still not properly likely due to dead battery. After revving the engine back and forth to see if that would effect the voltage it finally cut out on me and wouldn't even light up the dash when ignition was on. Turns out the fuse blew and so did the spare. I ordered a box of fuses and fitted the new battery. Box of fuses came and two more blew instantly. But none have blown since.

When I turn on the ignition now it doesn't prime the fuel pump (its completely silent) and now the engine light doesn't turn on. All indicators, brake lights etc seem to work fine though. When doing some electrical testing with my brother on the phone giving me instructions of what to test using my Haynes manual for the wiring chart we figured out the wiring works and produces continuity with the multimeter. So power is getting to the fuel pump and no wires are burnt out or broken, it's just not doing anything.

[Nobby the Bastard]

It's not your fuel pump, probably more ECU and associated items as it controls the fuel pump.

The blowing fuse issue clearly hasn't goneaway, something has failed and the short in it than caused the fuse blowing has now melted so it's open circuit.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Samon_x]

Thanks, I did wonder that. We tested the fuel pump by powering it up directly. I checked there was 12v getting to the pump + then grounded out the - pin to the battery, bypassing the ECU. It didn't do anything. I'm not ruling out ECU as well, but the pump didn't seem to power up in isolation either.

[WD Forte]

You're not giving us very accurate descriptions

What colour cables did you use to test the pump
The tank has 4 cables 2 for the fuel level sender 2 for the pump

The sender uses the Green and Black ( ground)
The pump uses Brown (power in) and Yellow which is pulled low
by the ECU to power the pump.

You'd need to put 12v on Brown and ground the Yellow to
say the Battery negative terminal test the pump in isolation.

You could just link the Yellow to the Black but this assumes the wiring is all good but we don't know that for sure.
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bikers smell of wee

[DrDonnyBrago]

Afternoon chaps.

I'm Samon's brother, I've been trying to help remotely by phone as I live miles away.

The last message was a copypaste of mine, apologies for lack of clarity.

He confirmed that the brown wire terminal at the pump (ignition switched live) was getting power, 12.5v to ground with the ignition on. Other components on this circuit such as lights/horn etc also function.

He attempted to check continuity across the yellow wire (pump connector neg to ECU) but I think this was difficult as the ECU plug connector block has infinitesimally small connections that didn't fit a probe (but samon can confirm).

He grounded the yellow wire at the pump connector to neg on the battery using a separate cable. He showed there was now 12.5v between brown and yellow at the pump connector block with a multimeter. The pump did not prime during this.

Cheers,

Donny

P.S. long time no see!

EDIT: the wiring diagram I'm using:
https://imgur.com/rNS7SKE

[Nobby the Bastard]

[DrDonnyBrago]

[Nobby the Bastard]

I would be tempted to do both pos and neg directly to the battery and take the rest of the bike completely out of the equation.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Nobby the Bastard]

Oh, and release the pressure in the fuel line. The pump may not be actuvating because there's sufficient pressure in the system.

Unlikely but possible.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[WD Forte]

As that Brown wire also powers other systems and you've strapped the yellow to battery neg, then I'd say that pump does look a bit
suspect.
But....
As Nobby says, it is just possible the system is already at working
pressure so may be not be activating because of that so releasing any/all pressure and testing again to be certain is an option.

Then there is the regulator which at working pressure cuts off
the power supply to the pump................
the ECU only allows it to run, it doesn't have any control over pressure.

The Fowlers one probably so expensive as it's the whole schmeer
Assembly, pump, filters, valves, regulator and fuel level sender combined
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bikers smell of wee

[Samon_x]

Hi, I did open the fuel cap before testing the wiring a while back. There was no pressure, no hiss or anything and it made no difference. I have not yet removed anything intricate like the whole pump assembly from the tank but I will do so to inspect it for anything obvious and will try brown wire straight to battery too.

Thank you for the advice and help. I'm open to any other tests, tips and suggestions and they're greatly appreciated.

[WD Forte]

There is no pressure in the tank, the fuel only gets pressurised after it enters the pump and then on to the injector.
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bikers smell of wee

[DrDonnyBrago]

Releasing the tank cap was to check there wasn't a blocked breather or something causing a vacuum, I had that issue on my CBR6 years back. Haven't checked releasing the fuel hose though, although in normal operation the bike does prime every time even if it's just primed, we will add it to the list.


We can try powering it directly from battery both yellow and brown wires, but I'm not convinced it will help. Am I correct in thinking if you power up the pump direct from battery it should make the same priming noise as it does in normal operation, but presumably continuously?

Cheers!

[WD Forte]

Yes and no.
Let's say we have an AOK YBR pump all connected up but we power it directly from a battery.
It should do the same as it does normally.
Start, run briefly then stop as it has an internal pressure switch/regulator

If it was free standing and not plumbed in it would run continuously
as it would never build enough pressure to trip the regulator switch.

My moneys on a bad pump because I don't think they hold pressure that long after power down.

If it doesn't run directly from a battery, I'd whip out and examine it closely before spending.
I'd check the pressure switch hasn't got stuck and the motor
still wont run with a direct feed to the terminals
(not via the pressure switch.)

I linked a motor filter kit before but you can get the whole
aftermarket assembly for £70 ish

https://www.ebay.co.uk/itm/304511331880?
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bikers smell of wee

[DrDonnyBrago]

Thanks, makes sense!

BW

Donny

[DrDonnyBrago]

The thot plickens...

Seems my recollection or more likely my instruction from the last phone session were lacking so I had Samon test it again to clarify a few things. Summary of outcomes:

The fuel pump direct to battery does prime it
The yellow wire from the fuel pump has continuity
The power supply to the fuel pump is good

There was an error with getting the yellow terminal to ground last time, so pump wiring is actually fine and we suspect the ECU.


The switched live (brown) power supply to the ECU seems ok (12.5v when on)
The earth wire on the ECU (black) has continuity to the battery neg
No EML light goes on when bike is turned on
No dial sweep or anything else when bike is turned on

Circuits not involving the ECU function (horn, starter, lights, etc).

Is there any meaningful way to test an ECU? It's a seamless black box of magic, apparently no obvious burnt bits from the outside. Perhaps checking if it gets spark?

Any way to guesswhether the ECU itself has fried or some wiring to it has fried?

Thanks again for everyone's advice.

[Nobby the Bastard]

Borrow an ecu for the same bike from someone else and see if it works. Are you sure you have replace all the blown fuses?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Kawasaki Jimbo]