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Project FZR fix up

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

  1. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  2. my67xr

    my67xr Well-Known Member Premium Member Contributing Member

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    Your 3LN1 carby's have different jetting and float height's than mine

    See number 3 below,
    I reckon the Float Height is causing the bog, so try setting the float height half a mm lower than it currently is set at
    Then try it out, warm the engine up and tune the mixture screw's to suit
    With the float height set too low it'll feel flat when you rev it, with it set too high it'll give you a hesitation/bog


    Here is a CV tuning guide from factoryPro

    Important notes about CV carb tuning

    To properly tune, you MUST:

    1. Have selected the BEST main jet for full throttle power (not just a "good" main jet - we mean "the BEST main jet" for power at high rpm).
    That eliminates the common severe tweaking of the midrange and lower tuning ranges to compensate for a "wrong" main jet.


    2. Then - select the BEST needle height / clip position for power at FULL THROTTLE / MIDRANGE after selecting the BEST main jet -
    That almost eliminates weird problems at cruise caused by tweaked needle heights that were required because the main jet wasn't correct.......


    3. Then, adjust the BEST Float Height for BEST FULL THROTTLE / LOW rpm (many Honda's excluded because floats are not adjustable) -
    You should be able to apply FULL THROTTLE at LOW RPM in TOP gear without ANY misfire of bogging or stumble.......


    If you follow that order, you will have:
    1. Best topend.
    2. Best midrange.
    3. Best low rpm power.


    Then - all you have left is dialing in the pilot circuit - i.e. mixture screw and pilot jet size - That's IT - Don't tweak needle heights and throw away full throttle midrange to try to fix a cruise issue (Unless you want to)
     
  3. Yetiburger

    Yetiburger Active Member Premium Member Contributing Member

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    ok i've redone the float levels and they are all within a mm of 9.2 mm above the line. its taking throttle way better even when cold. should I now wind the mixture screws in to the standard setting?
     
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  4. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    You need to find the setting that works best for your bike.
     
  5. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  6. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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    I mark the edge of the casing when the screws are turned in full, to help as a guide for 1 complete turn etc ... and also mark the edge of the screwdriver .... but that might just be old age creeping in.

    Set them to the 3LN1 base settings of 2 turns out, then just adjust by small increments as mentioned before .... every bike/carb is different


    pilot screw marked.jpg
     
  7. my67xr

    my67xr Well-Known Member Premium Member Contributing Member

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    I think the 9.2mm and 10.5mm fuel level's are a good base setting, but every carby can be different still
    Same thing with the mixture screw's base setting of 2 turn's out and 3 turn's out.

    In the end if it's not responsive off idle or has a slight bog/hesitation then i'd check the float's and lower them a touch if needed.
    Then warm up the bike to normal operating temperature and tune the mixture screw's to find the highest idle speed

    As i mentioned before,
    my FZR love's the mixture screw's all set leanish, so at the point the idle speed start's to drop, which on my bike is 1.75 turn's out
     
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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  9. Yetiburger

    Yetiburger Active Member Premium Member Contributing Member

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    Also has anybody put LED indicators on their bike? how would I know what resistors i need?
     
  10. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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    Mine has cheap China ones on the front and work without them
     
  11. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    Realistically you dont need to run resistors... You will need a LED Flasher can (cheap eBay one is fine) and if you only have 1 light on the dash for the indicators you can do the mod that is shown in this thread
    https://2fiftycc.com/index.php?threads/across-indicator-relay.9233/
    If you have a left and right globe in the dash just use the LED flasher can... much better than running resistors as they do get quite hot plus it saves a bit of power.. not really an issue with the FZR but on old Honda's every watt helps.. :)
     
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  12. Yetiburger

    Yetiburger Active Member Premium Member Contributing Member

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    awesome thanks. also how do you replace the bulbs in the dash?
     
  13. risky

    risky risky

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    underneath the dash.
     
  14. my67xr

    my67xr Well-Known Member Premium Member Contributing Member

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  15. Yetiburger

    Yetiburger Active Member Premium Member Contributing Member

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    cool. got them on the way. so cheap. also does anybody know where i can source a second hand r6 rear shock for the conversion?
     
  16. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  17. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    That flasher can is a ripper. I used it on the Across, so cheap and adjustable as well.
    It is a good buy.
    Good luck with finding an R6 shock, they do turn up every now and then.
    You will probably want the fork adjusters as well to be able to set the bike up properly at both ends.


    Sent from my iPhone using Tapatalk Pro
     
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  18. my67xr

    my67xr Well-Known Member Premium Member Contributing Member

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  19. my67xr

    my67xr Well-Known Member Premium Member Contributing Member

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  20. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    It would be interesting to see what differences there are in the rocker arm between the FZR250 and the R6R.
    the one I bought (now on the Hammertone Flyer Project X) was from an R6R..although I think all models 06 and up were R6R's but I could be wrong :)
     

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