NGK Spark Plug

Discussion in 'Motorized Bicycle General Discussion' started by MrLarkins, Aug 23, 2008.

  1. MrLarkins

    MrLarkins HS Math Teacher

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    What is the REAL difference between the B5HS, B6HS, and B7HS spark plug? I have the 6 and the 7. Don't know which is better and why it's better ^5
     
  2. Dave31

    Dave31 Moderator
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    They have a different heat range

    NGK.com
     
  3. pedalpower

    pedalpower New Member

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    iirc the 5 is hotter than the 6
     
  4. MrLarkins

    MrLarkins HS Math Teacher

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    6 is hotter than 7?
     
  5. Dave31

    Dave31 Moderator
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    [​IMG]



    For NGK spark plugs there is a simple rule of thumb:
    Low heat rating number (for inst. BP4ES) "Hot spark plug".
    high heat intake due to long insulator tip.
    High heat rating number (for inst. BP8ES) "Cold spark plug".
    Low heat intake, due to short insulator tip.
     
  6. MrLarkins

    MrLarkins HS Math Teacher

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    which is better for out happy times? i have the stock plug, a NGK B6HS, and a NGK B7HS

    which should i run?
     
  7. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    NGK B6HS but the 7 will work fine as well.
     
  8. misteright1_99

    misteright1_99 New Member

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    I run the B6HS and am very happy with it...
     
  9. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    Well done Guys! As a "loose" rule every step up in heat range adds 10 degrees to combustion temp @ time of fire in m/s-2 Or thats the theory.
     
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Would that be 10 degrees C or F?
     
  11. ebmvegan

    ebmvegan New Member

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    Which works best for ambient temps? some of us live in the desert where temps run over a 100 while others are in areas where ave temps are at 60.
     
  12. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    In the desert or so cal, a 6 is best.

    IMHO a 6 is the best bet for most of the country, with a 5 being a good selection for the cooler northern months.
     
  13. ebmvegan

    ebmvegan New Member

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    Thanks! Good to know.
     
  14. MarcPhotoMan

    MarcPhotoMan New Member

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    I have been running the BPR6HS it seems ok so far, anyone know the difference between this one and the B6HS?
     
  15. misteright1_99

    misteright1_99 New Member

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    That is a resistor plug......


    NGK Spark Plugs USA
     
    #15 misteright1_99, Aug 24, 2008
    Last edited: Aug 24, 2008
  16. MarcPhotoMan

    MarcPhotoMan New Member

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    good info but is it ok to use this plug on our bikes?
     
  17. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Resistor won't hurt anything, but it's the "P" part that bugs me. You don't want a projected tip, but I guess if it hasn't had piston contact, it's workin'! :)

    http://www.ngksparkplugs.com/docs/tech/partnumberkey.pdf
     
  18. MarcPhotoMan

    MarcPhotoMan New Member

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    funny thing is that it was cheaper than the regular plug, what do i look for to know if piston has had contact?
    And would this plug make it run hotter?

    I was able to easily get the bike above 50kmh - 30 mph but i backed off that type of speed on a bike worries me.
     
  19. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    You would know if the piston hit the plug. There is room. Effectively you raised your compression ratio, but it shouldn't run any hotter.
     
  20. Norman

    Norman LORD VADER Moderator
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    if the piston could tap the plug your gap would disappear in a heart beat and your engine would quit the plug would ground out and could do some damage to the piston and bearing and be bad for other parts in there.
    these engine have a hemi shaped combustion chamber and your plug would have to really stick down into the combustion chamber quite a bit to have the piston smack it.
    most stock reach plugs should not be a problem but if your worried best to measure the clearance with the piston a tdc and then measure the plug to make sure they don't touch each other.rotfl
     

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