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Project FZR400 Dragster

Discussion in 'Other Projects - Other Bikes (non 250's)' started by GreyImport, Oct 20, 2022.

  1. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Wow, they stung you on the postage considering it was only coming from Wollongong.
    I see you have resistor plugs, have you removed the resistors from the plug caps or are you resisting the resistors? :D
     
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  2. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    They are the plugs that were in it and Ill be replacing them
    So what happens if theres resistor caps on resistor plugs? .... reduced spark?

    From what I can find from other FZR400 models, NGK CR8E is standard

    This is the markings on the stock caps

    400 plug cap.jpg
     
    Last edited: Jan 17, 2023
  3. jmw76

    jmw76 Well-Known Member

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    Typically the high tension side of the ignition runs optimally with about 10k ohms of series resistance.
    This can often be made up with a mixture of resistors in the plug caps, resistor plugs and sometimes resistive plug leads. On cbrs they typically have 5k ohm resistors in the plug caps and 5k ohm resistor plugs. the plug wires are straight copper.
    You can measure each with a multimeter to see what they are. For plugs measure centre electrode to pin on the top. For plug caps measure between each end.
     
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  4. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Same as the FZR250


    CR8E are 5k

    Stock cap .... :idk:


    PXL_20230117_091230721 (Medium).jpg
     
  5. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    FWIW, just in case you've got errant plug cap resistor readings - if you look into the plug end of the cap and there's a slotted brass part, then it can be unscrewed and you'll find a resistor in there - got that far diagnosing YZF600 plug caps, I haven't located replacement resistors
     
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  6. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Yea Ive done that before with the 250 caps

    Theres no markings on the resistor but reads 9.5

    And my question would be surely Yamaha would have it correct from the factory

    Now does the little metal disc go back between the spring and the resistor? :cool:


    PXL_20230118_002256226 (Medium).jpg
     
    Last edited: Jan 18, 2023
  7. jmw76

    jmw76 Well-Known Member

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    I would expect that Yamaha had worked it out correctly.
    Secondary HT resistance on cars is often as high as 20k ohm.
    I wouldn't worry about it. If they all measure similar than you are good to go.
    If it an't broke, don't fix it.
     
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  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Thinking on it, I think the little metal disc should go between the spring and the resistor because it gets full circumference contact with the spring and full contact with the resistor.

    BTW, what spec does the manual give for the plug cap resistance?
    Is it 5K and that's what's got you flummoxed?
     
  9. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    That was my thinking also

    The "top" end of that spring had a little corrosion on it so Ill have to check the others

    I was just going on peoples comments :D

    The 3EN2 doesnt have a PDF manual but this I finally found from one of the other models

    cap resistance.jpg



    Carry on ... nothing to see here ..... :crazypilot:
     
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  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Upside, now you know for certain that it's within spec and need not be worried about again.
     
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