Wednesday, 9 July 2014

Yamaha YBR 125 fuel injection pump removal / refitting ( how to fit )

Yamaha YBR 125 workshop manual

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Yamaha YBR 125 parts in the USA 

just a quick post as today i had to change a fuel pump over , very easy job to do .
best to pressure check the fuel pump after fitting to ensure correct operating pressure .
see if there are any fuel pumps on ebay uk here or on Amazon uk here  .

you can also buy the internal pump unit for cheaper here on amazon uk or china here  .

other post of interest
Yamaha YBR 125 Fuel pump repair < replace internal fuel pump unit                  

                                             First mark exact pipe outlet position with marker

                                                 Remove the allen key headed bolts
                                       remove clamp
                              remove the pump from the tank be careful of the sender units float

yamaha ybr 125 fuel pump
                                                              The fuel pump itself
                                                Refitting is as easy as taking out just make sure the seal
                                                below is fitted correctly .

make sure the outlet aligned with removal mark 

finger tighnen the bolts 
                                                 then tighten the bolts in sequenece

                                i would then fit pressure tester and fit to bike to line test pressure

see more Yamaha YBR 125 blog posts 
thanks for reading the Yamaha Owners blog , if you would like to support us you can by  buying your newYamaha YBR 125 off ebay uk here or buying  parts for your yamaha YBR 125 from ebay uk here or you can buy a a Yamaha YBR 125 haynes manual of Amazon UK here or for YBR accessories at Amazon UK here  , or visit chinas online superstore here for very cheap motorcyle products direct from china .

You can also visit our sponsors website 125 sportsbikes and spares here .


  1. How did you open the cage to change the pump?

    1. Just been asked this -

      Take off the pipe and then split the pumps cage / body in half at the large tabs , its hardest bit and can break easy .

      make sure on rebuild all seals and joints are correct as you can lose pressure in these areas that creates bad running .

      I always check the fuel pressure after doing this make sure it holds

  2. Hiya, I have just replaced the fuel pump, just like in the tutorial, the fuel prime's on start but the engine is just turning over and wont start.

    What could be wrong?


    1. was it a faulty pump did you verify this if not it could be your original problem .

      im now assuming you confirmed fuel pump as faulty so it should run , it could be you fitted the internal pump wrong so you need to check fuel pump pressure to confirm this .

      anther thing i see sometimes is the injector plug connector being wrongly wired to a very simlar wire near the injector .

    2. I believe that I get weak/no fuel pressure (tester showed 0 on fuel pump prime start if I fitted it correctly), if I disconnect the fuel line, it just squirts a bit of fuel (very doubt it is 40psi).

      Inside fuel pump plastic assembly I only found 1 small O ring that should go on the actual fuel pump. I heard it is supposed to be 2 rubber O rings?

      (I have attached a picture from the web to show what O rings I am talking about )

      Hope that is clear

  3. Hi there, been reading your blog with interest as I have a YBR Custom '12. Anyway I replaced the fuel pump but I have a leak at the petrol cap, do you know if the seal can be replaced with a new one or if I will need a whole new petrol cap (which will mean two keys obviously). Cheers and keep up the blog, Steve.

    1. Thanks stevie ,

      Good question i dont know is the answer , i searched Yamaha parts
      and could not find a separate seal just replacement cap so it look like that only option .

      if you find anything let me know and ill add a post about it .

      YBR blog

    2. Hey, well I purchased another fuel cap, and yes you can disassemble them and replace the rubber ring, so I kept the old key and and I don't have to use two. It is a bit fiddly but with some grease to keep the little springs in place I eventually did it. If you want some pictures I took a few so you can see for yourself, but hopefully you won't ever have to do this! I recommend keeping the rubber seal from drying out, maybe with a tiny bit of grease. Mine had little cracks and dirt underneath, which obviously was clogging up the fuel filter too.

      I still have issues with the fuel pump not priming when the bike is hot, so a mechanic suggested I actually open my (now spare) fuel pump and sand down the propeller, so that it can't heat up and expand, but I am not sure how to actually get in to the unit itself as it seems pretty well sealed.


  4. Hi !

    The fuel pressure regulator is dead on my fuel pump ... and i'm unable to find this part.