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Thread: 1992 Yamaha Zeal FZX250 4 Cylinders

  1. #1
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    22nd July 2020 - 19:58
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    1992 Yamaha Zeal FZX250 4 Cylinders

    Kiaora, Tena Kotoa Katoa,

    I purchased this 1992 old beast on Fri. It started to jerk out a bit when I throttled in to climb up the hill taking her back home. On Sat I took her for a WOF check and Reg. On the way to those places she started to cut out when climbing up the hill whereby I have to shift the gear into a lower one. Later I was told that these old beast gave out a junk load of issues, especially to the cab, as their jet is so tiny. One reknown mechanic in West Auckland told me. And he wouldnt work on them.

    Would I still get parts for the carb in case the jet were totally blocked up? What's the best resolution to deal with the non synhcronising issue with the cab in relation to the shift of gear from upper to lower one. Any expertise advices here.?

    Nga Mihi e Hoa,

    Ko tene Greenhonnet

  2. #2
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    25th March 2004 - 17:22
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    Seems unfair. Two swaps in and everyone is unloading their poorly running bikes to each other.

    Still you might get away with this.

    Forget the synchonising for now. You are dealing with blocked jets and the passages that feed them. Pull them apart, pull out the jets and look through them. Compressed air helps hee. Someone you know must have a compressor?

    So the next step is to find all the passage ways from the bellmouth and blow through those too.

    Then the choke cct below the choke plungers and any passageways in the floatbowl. This got me last time and a tiny drillbit found a passage blocked I hadn't considered. But that's last resort. Dont want to oversize jet holes.

    And check floats are set about the same height, spend time watching YouTube videos on multi cylinder carbs maybe. There will always be things people miss. Ultrasonic bath may help but won't cure a decent blockage by itself often.

    Can of brake clean with tube trialing passageways may help - but use goggles for fuck sake.

    Careful to not damage diagram above carbs. Look for tears etc. Watch out for little o-rings when you take top caps off. Buy an impact driver, not to hammer but the bits are a good fit for undoing float bowls. Find the right size tools for undoing jets.

    Walk away and come back to try find what else you might have missed.
    Don't you look at my accountant.
    He's the only one I've got.

  3. #3
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    22nd July 2020 - 19:58
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    Sound like a big clean out on the carb

    I wonder how many hour would a decent mechanic would charge for a job like this?

  4. #4
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    If you gave him the complete bike. . . More than it's worth.
    Don't you look at my accountant.
    He's the only one I've got.

  5. #5
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    22nd July 2020 - 19:58
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    Oh my goodness.. The problem is...

    Quote Originally Posted by F5 Dave View Post
    If you gave him the complete bike. . . More than it's worth.
    Hey my bro Dave... The trouble is he doesn't only want the bike, but an arm and a leg of mine...

    Poor Honnet

  6. #6
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    25th June 2012 - 11:56
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    My step one would be check battery voltage at rest and running.

    Drain float bowls and tank and put fresh petrol in before worrying about any other more complicated issues.

    Also check for good spark from ignition and what plugs look like before going deeper.
    Govt gives you nothing because it creates nothing - Javier Milei

  7. #7
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    From memory, and it was decades ago, the BMW manual used to advise that in the event of a problem first thing was to check and clean (or replace) the fuel filter.. That can't hurt. If you're careful.
    There is a grey blur, and a green blur. I try to stay on the grey one. - Joey Dunlop

  8. #8
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    In line aftermarket fuel filters are notorious for causing kinks that block off fuel supply. Looks like you're doing it yourself. Watch lots of YouTube and get into it.
    Don't you look at my accountant.
    He's the only one I've got.

  9. #9
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    22nd July 2020 - 19:58
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    Too many chefs spoil the kitchen

    This render another classic example of too many chefs would spoiler the kitchen. I can be disagreed that you always start from the scratch in any endevour...


  10. #10
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    25th March 2004 - 17:22
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    Dude are you drunk?
    Don't you look at my accountant.
    He's the only one I've got.

  11. #11
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    24th September 2004 - 06:46
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    Quote Originally Posted by pritch View Post
    From memory, and it was decades ago, the BMW manual used to advise that in the event of a problem first thing was to check and clean (or replace) the fuel filter.. That can't hurt. If you're careful.
    When one becomes a gereatric like you Pumpkin one should never rely on ones memory for fault finding/servicing ones motorbicycles. It is unreliable.

    One should always refer to a reference whether it be hand written notes you have taken over the years or service manuals in digital pdf format or dead tree format. Either OEM or aftermarket such as Haynes or Clymer. Aftermarket manuals usually have tips on how to get things done with out using special tools like using the back wheel axle to remove an alternator rotor for example. Works treat on my '76 Honda CB550F Super Sport

    F5 Daves rant about kinked fuel lines with inline filters is funny as all hell Everyone I know who has fitted inline fuel filters, including yours truely, makes sure the fuel lines are not kinked before refitting the fuel lines back on to the fuel tank or carburetors.

    Here are some examples of dead tree references:-
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  12. #12
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    29th August 2005 - 11:53
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    There is a guy on the 2fiftycc.com forum that makes rebuild kits for these old carbs. As much as I love this place, that is the #1 forum for old small capacity bikes.

  13. #13
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    12th February 2004 - 10:29
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    Quote Originally Posted by crshbndct View Post
    There is a guy on the 2fiftycc.com forum that makes rebuild kits for these old carbs. As much as I love this place, that is the #1 forum for old small capacity bikes.
    Depending on the model there are complete carb rebuild kits. I'm guessing blocked jets if it doesn't like throttle, or maybe damaged diaphragms, or lots of things. This is why mechanics won't work on them, you can end up chasing your tail and the owner won't want to pay for it and then will be back in a week with another problem that supposedly you didn't fix last time and wanting you to fix it for free this time.
    Once/If you sort it out and it won't rev really high, don't be tempted to just hold it. "EVERY" FZR250 I have checked had valve springs that were over the specified installed height. They are notorious for bending and dropping valves. The valve springs are the only fault I have ever found. Mechanically the rest of the engine is a gem.

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