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Problem with FZR fuel pump maby?

Discussion in 'Yamaha 250cc In-Line 4's' started by JeremyHill, May 27, 2010.

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  1. jonno_913ln6

    jonno_913ln6 New Member

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    if your burning some crap fuel at the bottom of the tank the plugs could foul up more quickly.
    my bike had the same problem, i checked fuel, charge and spark, all seemed fine, then after jiggling the spark leads she fired straight
    up again. i replaced the plugs and leads and it goes fine but i still get the uncontrollable power loss to stall if i select a gear to high
    for a hill but it always starts again after the plugs and leads wer changed, so you can try this but im not even sure myself as to why
    exactly it does this.
     
    jonno_913ln6, Feb 8, 2011
    #41
  2. SnowFox

    SnowFox New Member

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    Dont quote me on this, but i think your flooding the engine lol.
     
    SnowFox, Feb 8, 2011
    #42
  3. dave

    dave Well-Known Member

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    Sounds like it starves for fuel going uphill

    When my EXUP was tied up (fully open) it did a similar thing. It would die off under load, up hill, below 7,000 rpm
     
    dave, Feb 8, 2011
    #43
  4. jonno_913ln6

    jonno_913ln6 New Member

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    honestly, both could potentially be the problem and i know these bikes don't have a heap
    of torque down low but it doesn't seem feasible that it would flood, seeing as im not one to be fearfull
    of getting the revs up there to climb a hill but i guess it is possible. if so its quite a temperamental bike.
     
    jonno_913ln6, Feb 9, 2011
    #44
  5. JeremyHill

    JeremyHill New Member

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    Hey guys, it's me again sorry it's been awile but my little fizzer has been acting up again lately.
    I start her up fine ride to uni and back everyday but for some reason on longer rides, or just after a period of say 3 months of normal riding it has problems.
    I went for a ride today and herd the engines note change and lost alot of low end power, seems fine past 10000rpm but below that it splutters and pops (not severely)
    When i got home i turned it off, and after 1minute tryed to start it again, i noticed that the fuel pump was ticking alot (it doesn't usualy do this straight after a ride. when it does this right after a ride there is usualy a problem as theres no pressure in the carbs) so i opened the gas cap, turned the bike on and off and herd it slow down and get pressure again. started it and it ran like it was on 3 cylinders, turned it off tryed again with the cap open switching it on and off geting the pump to get pressure and started it she ran fine.

    So my question is, would a blocked fuel tank cap vent cause spluttering in low revs but run fine after that (it doesn't make sense), this has happened before and after awile the 3rd cylinder dropped and i had to clean all the plugs (done this many times "carbon fouled") also i'm still running the stock air filter, with an open exhaust, should i get a high flow pod or something (i can't find another panel one) as this may be causing it too run too rich and foul.

    Thanks alot guys.
     
    JeremyHill, Jun 28, 2011
    #45
  6. dave

    dave Well-Known Member

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    1) running rich
    2) Wrong temperature plugs
    3) Using Shell Ultra petrol
    4) oil in the fuel (or leaking oil rings)
    5) not working the engine hard enough.

    Does that help?
     
    dave, Jun 29, 2011
    #46
  7. JeremyHill

    JeremyHill New Member

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    I am running the right temp plug's CR8's and i ride to 16000 rpm atleast once a day, i don't use shell, and in my previous post, i was wondering if some pods would lean me out a bit, as i have a restrictive panel stock airfilter, and a open exhaust. Hoping i don't have to change jet sizes.

    Plus my fuel cap might be clogged i think, i jsut didn't get how it would cause it to splutter at low revs but be fine at high revs, as the vacuum should restrict fuel through the hole rpm range...

    So i'm guessing it's my airfilter.

    And my carbs have been done, all floats, emulsion tubes checked.. should be fine.

    Thanks for the reply though dave.
     
    JeremyHill, Jun 30, 2011
    #47
  8. dontz125

    dontz125 Active Member

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    Open exhaust should lean you out dangerously, implying your air filter is seriously clogged to run rich. You may actually have something plugging the intake snorkel.

    What jets are you currently running?

    You are correct about the cap vent - a partially obstructed vent will draw down the tank which will cause more problems at WFO than idle.

    Why are you running open exhaust? There is no performance benefit to be gained on a street bike, and only bad press.
     
    dontz125, Jun 30, 2011
    #48
  9. JeremyHill

    JeremyHill New Member

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    I bought the bike originaly with the exhaust, as far as i know it's open, it's a DIC bannana pipe and it's pretty loud. I don't know what jet's i am using.

    I heard FZR's come factory running quite rich, so i wouldn't think an open exhaust would cause any harm, plus she's deffinitly not running lean, she floods real easy on startup, sometimes splutters at low rpms and bogs down.

    After long rides i here a note change in the engine and i lose alot of power, i checked the pipes and it seems it is running on all four cylinders....but this has happened many times and eventualy it dropped cylinder 3 from fouling.

    TBH i'm not sure what's wrong with it, maybe i could make an air filter out of some foam my stock paper one looks clean, but maybe it's clogged?

    When riding for a long time (especialy at high rpm) is when it changes note, the higher the rpm, the faster it changes note and loses power(weird?) so i thought it was the tank cap vacuum or airfilter i dunno.

    How do i clear the tank cap of the blockage, not sure where the vent is?

    thanks
     
    JeremyHill, Jun 30, 2011
    #49
  10. dave

    dave Well-Known Member

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    Running better at high revs that at idle speed would be a symptom of leaking float valves in the carbs. At low fuel usage the float bowls fill up with more fuel than is used and then the mixture gets progressively richer. You would notice this when you pull up and idle for a while and the engine progressively runs worse until you get going hard again

    At faster speeds the float valve leakage is less than what is being used and they are able to control the level at the higher fuel usage rate.

    It might not be the cause of your problem but it is what I would look at first..

    Noting that it drops no3 with a fouled plug I would look at no3 carb and confirm the float level is the same as the others.
    It could just have some rubbish stuck in the float valve.

    Hope that helps
     
    dave, Jun 30, 2011
    #50
  11. JeremyHill

    JeremyHill New Member

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    That's a good suggestion, but the problem with that is it may run good at higher revs...but only for a while, running in the high rev zone actualy makes the note change and engine power decrease symptom show qicker. Plus my bike has no problems idleing, i don't have problems at stoplights unleas that symptom i spoke about earlier arrives. It usualy comes after a long straight going 100k's, at say 15000 revs, then as i slow down to rest at a stop light, i hear the note of the engine change, a few pops in the exhaust and after that loss of alot of power. After i get home it sits for a few, i start it back up and it runs fine.

    Thanks for the input.
     
    JeremyHill, Jul 5, 2011
    #51
  12. dave

    dave Well-Known Member

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    I'm stuck for ideas.... <!-- s:???: --><img src="{SMILIES_PATH}/icon_confused.gif" alt=":???:" title="Confused" /><!-- s:???: -->
     
    dave, Jul 5, 2011
    #52
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