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How to check if fuel pump broken? gt250r

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  • How to check if fuel pump broken? gt250r

    My gt250r has been stalling randomly when i'm coming to stop a bit in the last couple of days.. I put it down to hot days and the fact that oil cooled bikes don't always cool themselves the best on them, however on my way home today the bikes engine cut out with electrics still working fine, no warning lights or anything, just no fuel obviously getting to the engine. When I start the bike up what I assume is the fuel pump (This is my first bike so i'm no expert on them) makes quiet a loud buzz but I figured that was normal since a lot of car fuel pumps do that too. It is still making the buzz but the bike has had plenty of time to cool down (including while I walked it 500 meters to my house since it wouldn't start) but the starter motor just turns over and absolutely nothing else happens. Have tried disconnecting the battery and reconnecting it just incase that would reset it if it was something electrical with no luck. Also bike doesn't seem to have been accelerating as good as it used to for the last couple of days while it's been stalling.

  • #2
    Do you ever touch the starter button before the fuel pump has fully primed and the tacho sweep finished?
    or touch the throttle before the engine has resumed normal idle speed on startup?

    Its a long shot, but its very common on people with their first fuel injected bike, especially affecting single and twin cyl bikes.

    I solved the 'cbr250 stalling, lets call the lawyers' phenomenon once I saw vids of their starting procedure, mashing the throttle within seconds of turning the key on.
    many never admitted it but never posted the problem again.

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    • #3
      Originally posted by Aufitt View Post
      Do you ever touch the starter button before the fuel pump has fully primed and the tacho sweep finished?
      or touch the throttle before the engine has resumed normal idle speed on startup?

      Its a long shot, but its very common on people with their first fuel injected bike, especially affecting single and twin cyl bikes.

      I solved the 'cbr250 stalling, lets call the lawyers' phenomenon once I saw vids of their starting procedure, mashing the throttle within seconds of turning the key on.
      many never admitted it but never posted the problem again.
      Nah I read about that for some reason a while ago too, and it wouldn't explain the randomly just cutting out while I was riding along at about 70kph that it hasn't started since :/ Only thing I can think of that would cause that with no warning lights is fuel pump being fucked (and even then it seems strange to go that suddenly).

      I just pulled the fuel tank off checked one of the spark plugs (it was all good, other ones hard to get to but it wasn't missing before so I really doubt the spark plugs are just gone and if atleast one is sparking then as far as I know it should start even if it stalls immediately after, at the momen't starter motor turns over but nothing at all happens otherwise.

      Not sure how someone with limited tools/knowledge would go about checking if the fuel pump is pumping without getting fuel everywhere... is the fuel pump in the fuel tank or somewhere else? if fuel tank I guess I can just try undoing the fuel line with a jar underneath and turn the engine over and see if anything squirts in? Either way the fuel tank still buzzes on startup which makes me not entirely certain it's likely to be that :/.

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      • #4
        easiest place to start, the fuel pump should pump when the key is turned on then stop or slow once pressurised, if it doesn't do this then it isn't pumping enough and has either failed or the pickup may be blocked

        next time it stop open the tank cap and see if it has created a vacuum, this will mean that one of your vents is blocked, could be a pinched hose from taking the tank off and putting it back with the hose in the wrong place.
        Do you remember the good old days before the internet?

        when arguments were only entered into by the physically or intellectually able.

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        • #5
          Originally posted by filbert View Post
          easiest place to start, the fuel pump should pump when the key is turned on then stop or slow once pressurised, if it doesn't do this then it isn't pumping enough and has either failed or the pickup may be blocked

          next time it stop open the tank cap and see if it has created a vacuum, this will mean that one of your vents is blocked, could be a pinched hose from taking the tank off and putting it back with the hose in the wrong place.
          Need to get it to start before it can stop again :/ Although the gt250r is pretty straight forward as far as taking the tank off and where the hoses under it are, I can just peek through the flairing and see they are all where they should be. I assume there would never be a vacuume in the tank due to the hose coming out of it to the ground for when it's overfilled or whatever unless that's one way somehow.

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          • #6
            you don't need to get it to start, it's part of the startup sweep when you turn the key on, once cranked the pressure should drop or once turned off the pressure should drop off after a few minutes and you'll hear the pump when you turn the key on again.

            wondering if this is the usual sidestand switch failure though, they stop any time or on bumps until you replace or bypass the switch
            Do you remember the good old days before the internet?

            when arguments were only entered into by the physically or intellectually able.

            Comment


            • #7
              Originally posted by filbert View Post
              you don't need to get it to start, it's part of the startup sweep when you turn the key on, once cranked the pressure should drop or once turned off the pressure should drop off after a few minutes and you'll hear the pump when you turn the key on again.

              wondering if this is the usual sidestand switch failure though, they stop any time or on bumps until you replace or bypass the switch
              I've been googling non stop as I want it fixed and saw the side stand thing but it won't start in neutral and when the side stands down in first the starter motor shouldn't turn but it does still so I don't think it's that.
              Just went and turned it to on then off and opened tank. No vaccume, but I noticed that before I pulled the fuel tank off I was reading 2 bars of fuel. When I pulled it off there was very little in there and now it's flashing that it's on reserve or empty (maybe 100mils max spilt from the tank while it was off).... I am now thinking that maybe i've blown a fuel hose... Will try and get someone to bring a jerry can around and check. Should be easy if it pressurises as soon as you flick the on switch. Not sure how likely it is but all the fuel ending up on the ground instead of in my engine would explain why it stopped so suddenly and won't start now.... Will follow the fuel hose with my fingers in the mean time see where that gets me .

              Comment


              • #8
                Just checked that fuel pipe though and it seems it's a single bit of pipe that doesn't go very far and visually still appears perfect (will top the fuel up a bit and see how that goes though) Unless there is a leak there should have still been plenty of fuel so...

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                • #9
                  Originally posted by filbert View Post
                  you don't need to get it to start, it's part of the startup sweep when you turn the key on, once cranked the pressure should drop or once turned off the pressure should drop off after a few minutes and you'll hear the pump when you turn the key on again.

                  wondering if this is the usual sidestand switch failure though, they stop any time or on bumps until you replace or bypass the switch
                  I didnt realize they had a side stand switch that would explain it, he should bypass it and then if thats not it check the fuel pressure an efi motor will idle with a partially blocked filter, maybe check the vacuum fuel tap is supplying fuel.

                  Comment


                  • #10
                    Now the fuel tank is off and you have removed the air cleaner dribble a little bit of fuel down the throttle bodies...

                    Now try and start it...

                    If it starts you definitely aren't getting fuel...

                    This is your first step in fault finding...

                    Then you need to hook a hose to the fuel tank outlet and put power to the pump to see if it flows fuel...

                    - - - Updated - - -

                    And check the fuses...

                    Don't just look at them, multimeter them for continuity...

                    Comment


                    • #11
                      Originally posted by Rich... View Post
                      Now the fuel tank is off and you have removed the air cleaner dribble a little bit of fuel down the throttle bodies...

                      Now try and start it...

                      If it starts you definitely aren't getting fuel...

                      This is your first step in fault finding...

                      Then you need to hook a hose to the fuel tank outlet and put power to the pump to see if it flows fuel...

                      - - - Updated - - -

                      And check the fuses...

                      Don't just look at them, multimeter them for continuity...
                      Thanks, this the answer I was hoping for. Will give those a go . I just removed air filter but can removed the whole box but pouring fuel down anywhere won't help when it's EFI will it?

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                      • #12
                        Don't have a multimeter...

                        Some wire a battery and a globe will work...

                        Hell, some wire a 9 volt battery and your tongue will work...

                        Comment


                        • #13
                          Originally posted by fetus View Post
                          Thanks, this the answer I was hoping for. Will give those a go . I just removed air filter but can removed the whole box but pouring fuel down anywhere won't help when it's EFI will it?
                          Pull the plug / plugs out give the cylinder a squirt of fuel replace the plugs if it fires then rich is right its a fuel problem.

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                          • #14
                            Can you see the throttle boody butterflies moving when you turn the throttle with the air cleaner not in place?

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