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Project FZR fix up

Discussion in 'Your 250cc Projects' started by Yetiburger, Oct 7, 2017.

  1. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Do you let it idle up till it's about 1/4 temperature before you are trying to rev it?

    You may need to sync the carb's if the slide are all moving randomly, they should be even
     
  2. Yetiburger

    Yetiburger Well-Known Member

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    ok so I let it warm up and it idles fine. then bogs when i twist the throttle and then revs when i back it off.
     
  3. Yetiburger

    Yetiburger Well-Known Member

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    I cant seem to find what the mixture screws are meant to be set too. I remember it better two and a half turns out? is this correct?
     
  4. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  5. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Start the mixture screw's at 3 turn's out, start the bike and let it get to operating temperature then tune from there
     
  6. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    After fitting the Keyster kit's to my 3LN3 and replacing the manifold boot's and airbox boot's i have my mixture's set to 1.75 turn's out atm
    It's been pretty warm over here for the last few week's and my bike felt a little sluggish, so this morning i changed the mixture screw's from 2 turn's out back to 1.75 and it feel's better now.
     
  7. Yetiburger

    Yetiburger Well-Known Member

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    ok so i've set the mixture screw in and out to a few different settings but it seems to have no effect on it bogging when the throttle is opened.
     
  8. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    What fuel level are you running in them ?
    And sorry, i've forgotten, were they 3LN1 carb's or 3LN3 carb's
     
  9. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Are you doing this with the airbox fitted?
     
  10. Yetiburger

    Yetiburger Well-Known Member

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    they are 3ln1 carbs. this is without the airbox fitted have new boots on the way. on the float levels are 15mm, 15mm, 19mm and 35mm. so they are definitely a bit messed up but how do you actually change what the levels are? also would this be causing the bike to die under throttle?
     
  11. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Adjusting the float level's is pretty easy, take the float out and use a pin in the hole on the float tab to bend the tab either way
    They all need to be spot on otherwise it will cause a rich or lean condition for that cylinder.
    It won't rev nice with the airbox off, it'll be too lean


    The float's should sit 16mm off the fuel bowl mounting face when the needle pin is just toughing the tab
    You can cut a 16mm deep piece out of an old card to use as a guide to adjust them
    FloatLevel_Yamaha_FZR250.jpg

    If you move the pin to the right and bend the tab a little, in the pic below, you will lower the float level
    If you move the pin the the left and bend that tab up it will raise the float level
    [​IMG]

    You can also check the fuel level with a piece of clear tubing on the drain loosen the drain screw with the clear tubing going up above the carby, the fuel level should be 9,2mm above the line on the fuel bowl
    Mark a line on the tube, then a second line 9.2mm further up, put the first line level with the line on the fuel bowl and when you open the drain screw the level should come up to the second line you marked

    [​IMG]
     
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    Last edited: Feb 9, 2018
  12. Yetiburger

    Yetiburger Well-Known Member

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    awesome thanks. ill give it a crack tomorrow. ill put the air box on with the shrunken boots till the new ones show up.
     
  13. Yetiburger

    Yetiburger Well-Known Member

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    so i got the float levels close and crudely fitting the airbox with the badly shrunken airbox boots and it now runs and revs. it's not perfect but I still need to fit the exup cables. So hopefully with that and new boots and a bit more adjustment of the float levels it will run a lot better.
     
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  14. Yetiburger

    Yetiburger Well-Known Member

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    I saw a thread on here a while ago of somebody fixing the fairings by plastic welding etc. does anybody know where to find this thread? i'm going to have a go at fixing up the broken ones I got with the bike.
     
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  15. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  16. Yetiburger

    Yetiburger Well-Known Member

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    ok so i'm going to try and repair my fairings. they all have various cracks and chips etc. but the left side fairing has a large piece missing. Could anybody show me some photos of the left hand side fairing and the front fairing (mainly up by where the mirror sits). the following photos are what i'm working with. was going to chop up the other right hand side fairing to make parts for the left. 20180215_171140.jpg 20180215_171157.jpg 20180215_171207.jpg
     
  17. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    umabeven.jpg 3fzr.jpg 1fzr.jpg 11fzr.jpg
     
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  18. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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  19. Yetiburger

    Yetiburger Well-Known Member

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    yeah those guys don't seem to have anything i need.
     
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  20. Yetiburger

    Yetiburger Well-Known Member

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    I mean whats the worst that can happen. 20180217_170640.jpg 20180217_171913.jpg 20180217_172712.jpg
     

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