Compatible plugs?

Discussion in 'Introduce Yourself' started by raimond, May 31, 2010.

  1. raimond

    raimond New Member

    Hi everybody!
    Im new in this amazing forum.

    My plug is dead and i want to know compatible plugs for my 80cc engine.
    The original plug is the Z4C...but here where i live i dont find it.

    Could you tell me different models of plugs compatibles with an 80cc engine??

    Thanks a lot!!!
     

  2. Fabian

    Fabian Well-Known Member

    This is a copy of my previous post on the issue.

    Ok, been doing some research as to alternative plugs for the NGK BP*HS series that we seem to commonly use in our Happy Time or China Girl 2-stroke engines.

    Cross reference part numbers and equivalents.

    NGK BP5HS = Denso W16FP-U or Denso Iridium IWF 16 = Bosch W8B or W8BC or W8BP = Champion L92Y
    NGK BP6HS = Denso W20FP-U or Denso Iridium IWF 20 = Bosch W7B or W7BC or W7BP = Champion L87Y
    NGK BP7HS = Denso W22FP-U or Denso Iridium IWF 22 = Bosch W5B or W5BC or W5BP = Champion L64Y
    NGK BP8HS = Denso W24FP-U or Denso Iridium IWF 24 = Bosch = None......................= Champion L61Y

    Unfortunately, neither Denso or NGK manufacture a supplementary gap spark plug (multi pronged) to suit a 12.7mm thread reach.
    With NGK, each heat range figure gives 70 degrees celcius (158 degrees fahrenheit) temperature differential at the firing tip, to the next heat range above or below the nominated sparkplug.
    So, a BP7HS runs 70 degrees hotter than a BP8HS or 70 degrees cooler than a BP6HS sparkplug.

    Now you can go out and play till your hearts content.


    Fabian
     
    Last edited: May 31, 2010
  3. raimond

    raimond New Member

    thanks for the answer.

    So, all this models are ok for a 80cc engine?:

    NGK BP5HS = Denso W16FP-U or Denso Iridium IWF 16 = Bosch W8B or W8BC or W8BP = Champion L92Y
    NGK BP6HS = Denso W20FP-U or Denso Iridium IWF 20 = Bosch W7B or W7BC or W7BP = Champion L87Y
    NGK BP7HS = Denso W22FP-U or Denso Iridium IWF 22 = Bosch W5B or W5BC or W5BP = Champion L64Y
    NGK BP8HS = Denso W24FP-U or Denso Iridium IWF 24 = Bosch = None......................= Champion L61Y


    What is better? A plug that runs hotter or cooler??Which is the diference??
    Thanks!
     
  4. Fabian

    Fabian Well-Known Member

    Yes raimond,

    They should all fit the spark plug hole and thread of 2-stroke bicycle engines.
    There is no such thing as a plug being better.
    There is only one answer to your question and that is "which plug heat range is correct for your air/fuel ratio" and engine loading, of which, there is extensive information on how to select the correct heat range, using the search function on the site and freely available information on the internet.

    A general rule of thumb is to use an NGk BP6HS or a BP7HS if you run long periods of wide open throttle in a warmer climate.
    I use an NGK BP8HS but my application is tortuous on the engine due to a heavy trailer being towed at low speeds.
    The consequence of using a BP8HS is of poor cold start operation where the plug doesn't hold enough temperature to burn away carbon deposits untill the engine has sufficiently warmed up. It coughs and splutters and runs cantankerously for the first 2 minutes of operation.

    NGK makes excellent plugs but they don't make an Iridium tiped plug, of which you need to run Denso if you so desire to use Iridium.
    There are other manufacturers of spark plugs that will work with these 2-stroke engines, but i've only listed the most common types by large and well respected companies.
    You could take any of these manufacturers and cross reference their part numbers to another manufacturers spark plug application charts if it's not listed in my post.

    Someone else mentioned that the "E3" brand of spark plugs should fit these engines. On paper they are a good design, being very similar to a supplementary gap spark plug.
    The code is "E3 12"

    Fabian
     
    Last edited: May 31, 2010
  5. Pablo

    Pablo Motored Bikes Sponsor

    NGK BPR6HIX
     
  6. Fabian

    Fabian Well-Known Member

    Paul, you are correct.
    I did not research their resistor plug series, just the non resistor type, of which Denso happens to make in Iridium.

    Fabian
     
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