B8HS-10 plug

Discussion in 'Motorized Bicycle General Discussion' started by fischer550, Jun 12, 2014.

  1. fischer550

    fischer550 Member

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    So I bought a top end kit from fred at crmachine.com to put on my dax gen IV bottom end. The top end came with a cylinder (decked and ported), a 6.0 chamber head, cut piston, and a NGK B8HS-10 spark plug. Does the 10 refer to the plug gap? And I am switching to opti-2 pretty soon, in which people are saying that the plug will not turn light tan unless you switch to a hotter plug (b6hs) should I order some B6HS-10 plugs or what? Don't really know anything about plug heat range/plug gap stuff.
     
  2. Davezilla

    Davezilla New Member

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    the 10 is the heat range of the plug, and NGK heat ranges go with the bigger the number the colder the plug... That plug should work, but if it's not "self cleaning" it's self good enough you may need to go with a #6 or #7 heat range...
     
  3. fischer550

    fischer550 Member

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    I thought the "8" in B8HS-10 was the heat range?
     
  4. xseler

    xseler Well-Known Member

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    The 8 is the heat range. Usually the 10 means that the case pack is 10 units.

    I run the 7 here in Oklahoma. Seems to be about the best compromise --- though I do have a 6 that I use in the cooler weather.

    Good luck!


    (Remember that NGK is the only one that uses higher #'s for cooler plugs....)
     
  5. Desert Rat

    Desert Rat New Member

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    so with 110 degree weather which one would be recommended for the desert
    about 2000 ft elevation?

    66cc 2 stroke
    32 to 1 oil mix
     
  6. Davezilla

    Davezilla New Member

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    You're right... I wasn't seeing that last night when I replied... been awake way too long.
     
  7. mapbike

    mapbike Active Member

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    I run the 6 heat range in my engines year around and no issues.

    And I ride in the Texas Heat where we dont get quite as hot as you do there but sometimes we have a couple months of triple digit temps every single day, I do run heads on my engines that allow them to cool a bit better also, so that is probably a big help with keeping them cooler even when running the #6 heat range plug.

    with a standard china head you might be good in that heat by using the #8 cooler range plug... I'm sure other here can give better advice on this than I can but I like the BH6S plug year around, never had one crap out on me yet and I'm still running the same plug in engine that have been going since 2009.
     
  8. fischer550

    fischer550 Member

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    Would a hotter range plug run better than a colder range? I am curious why exactly you choose the 6 over the 8, runs better?
     
  9. mapbike

    mapbike Active Member

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    I dont know if it runs better or not, I've never run the cooler range plugs.

    One thing that needs to be understood about a plugs heat range difference is that the heat range has nothing to do with how hot or strong the spark is, Each plug fires the exact same spark, it actually has to do with how hot the plug itself runs since the porcelain in the hotter plug is narrower inside plug body and allows gases and compression to happen farther up into the spark plug itself while a colder running plug does just the opposite.

    On my old hot rods I would always run a. Cold plug and a hot coil since they were high compression engines for the street, to hot of a plug increases detonation/preignition problems sometimes.

    In very hot conditions with a china girl that is very high compression the colder plug may be the best option.

    Map
     
  10. Goat Herder

    Goat Herder Gutter Rider

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    I would say from what Boss man told me in the small engine shop I work in was. He said at our higher altitude that it promoted a cleaner plug as in it was the best match to self clean itself. We are up pretty high in the mountains here where chain saws run.
     
  11. Goat Herder

    Goat Herder Gutter Rider

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    We ran pretty hot plugs for that altitude. For my mini dragster motor bike. I run as hot a plug as I can get. I am also dumping fuel and oil in this pig ''two stroke''

    In all our small two stroke engines we ran a spark plug with a protruding electrode. Those plugs stayed clean and fowled less than everything else would in a small two stroke.

    Looks like this. This is just some generic picture. Yet you can see what I mean . The insulater is slighty past the threads.[​IMG]
     
  12. FFV8

    FFV8 New Member

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    The -10 suffix on NGK numbers is the gap in millimeters. That plug is pre-gapped @ 1.0mm or .040 inches.

    The rule of thumb on air cooled 2 strokes is to run the coldest plug that you can. The plug is only too cold if it fouls easily. if you can run an 8 or 9 heat range in NGK without fouling then use that. If the 8 fouls after a couple of tanks of fuel, step up to a 7.

    A cold plug does not cost you power, but a plug that is too hot can cost you an engine.

    .
     
  13. mapbike

    mapbike Active Member

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    Ditto on the extended electrode plugs, thats what I always ran in my 2 stroke dirt bikes because I had much less issue with fouling them.
     

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