Motorized Bicycle Aftermarket Spark Plugs

Discussion in 'Instructions for Building and Repairing Motorized ' started by Down_South, Aug 21, 2009.

  1. Down_South

    Down_South New Member

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    OK, so I've done some research on spark plugs and have listed every brand from around the world that has a plug for these 2 stroke bike engine kits. My goal is to make a list that anyone can use no matter where they live. Feel free to add any other plugs that have the physical dimensions of 14mm diameter with 1.25 Threads Per mm and 1/2" reach ( 12mm and .472" reach is acceptable). Heat range and resistance can vary but the physical dimensions should remain within above specs.

    Spark Plug:
    Accel - 0453
    AC Delco - R44F
    Autolite - 4123, 425, 275, 4093, XS4093
    Beru - 14R-7BU
    Bosch - WR6BC+, WR7BC+
    Champion - L82YC, RL82YC, L86C
    Daytona Maxfire - 61490
    Denso - W20FPR-U, IWF20
    E3 - E3.32
    Eyquem - 775SX
    Motorcraft - AER32
    NGK - B6HS, B7HS, BP6HS, BP7HS, BPR6HS, BPR7HS, BPR6HIX, BPR7HIX
    SplitFire - SF265F, SF412C <--- both discontinued - Shucks!!
    Torch - E6TC, E6RTC

    Also, for those of you who are looking for a "shorty" plug for a tight fitting engine, I managed to find some 3/8" reach plugs that will fit just fine in the stock heads that came with 1/2" reach plugs.

    Autolite - 2974, XST2974, 254, XST254 ( The 254 has a solid terminal bud that won't work with the stock cap, if this is a problem, use the 2974 which has a threaded terminal bud. )
    NGK - BM7

    I've attached a picture of the stock Chinese plug that came with my engine. The picture shows a clear cross reference to a NGK BP7HS. I really learned a lot about spark plug companies while making the list. I haven't heard of some of them until now.

    DISCLAIMER: Not responsible for any damages. Double check my info before buying and make sure that the new plug matches up with the stock plug that came with your engine unless you're using "shorty" plugs. Have fun and ride safe.
     

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    #1 Down_South, Aug 21, 2009
    Last edited: Jul 5, 2010
  2. TheE

    TheE New Member

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    Champion L86C works well in my 49cc engine.
     
  3. Down_South

    Down_South New Member

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    OK, it checks out, I'll add it to the list. Thanks
     
  4. Kevlarr

    Kevlarr New Member

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    Guess you haven't heard the old saying, "Pistons, the breakfast of Champions!" :D
     
  5. Down_South

    Down_South New Member

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    Yep, I have a John Deere tractor that uses the Champion 71 (RC12YC) plug and I switched over to the Autolite 3924. I like to get out the DMM/DVOM/Ohm meter and check plug resistance. The Champion 71 measured in at 15.1K and the Autolite 3924 measured in at 4.82K, so I use the Autolite. Too much resistance can fry the ignition coil.
     
  6. Kevron99

    Kevron99 New Member

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    I got a Denso Iridium IWF20 on my 50cc Starfire GEN IIA. The bike starts with 2 pedal kick.
     
  7. Down_South

    Down_South New Member

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    Yep, That's a really nice plug too! Haven't tried it yet, but I've tried the Iridium IX and the Autolite XS4093 and the engine runs smooth as butter.
     

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