School me Sparky!! - Spark Plug Variety

Discussion in 'Trials' started by Greebe, Nov 1, 2018.

  1. Greebe

    Greebe Been here awhile

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    So I was looking at getting a few extra spark plugs ordered for my 2017 Scorpa Factory 300, and see that there are at least four or five different ones plus several Iridium variations.

    The plug on my bike is the Denso W16FPR-U, but have not found this plug anywhere, only the NGK made plugs.

    Not being a spark plug meister, I really do not know what would be different about all these NGK plugs and why there are so many different opinions from online retailers on which spark plug to use for this bike.

    Any thoughts?

    Thanks a lot,
    Greebe



    Here is what I have found along with their description of the plug:

    Scorpa Manual:

    NGK BP5ES
    or
    Denso W16EP-U (Equivalent)



    Splatshop:

    BPR5HS

    2017 Sherco ST Factory
    2017 Scorpa Factory
    2018 Sherco onwards
    2018 Scorpa onwards

    NGK BP5ES

    Standard spark plug for all Sherco trials bikes except the 50cc



    Jacks Cycle:

    NGK BPR5ES or upgrade to
    BPR5EIX

    For Sherco and Scorpa



    RYP USA:

    NGK BP5HS

    This is the spark plug for the 2017 and 2018 Factory Sherco and Scorpa Trials motorcycles.


    .......................
    #1
  2. heffergm

    heffergm Long timer

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    BPR5ES is a standard resistor (R) plug. BP5ES is the same standard plug without the resistor. The resistor plug is really more for cars with a lot of electrics that might cause interference, you can run either.

    BPR5EIX is the iridium variant of the above, again with resistor.

    The rest I know nothing about. Were I you, I'd just run standard copper plugs (BPR5ES or BP5ES) and make sure they're gapped correctly. Iridium just lasts longer.
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  3. fprintf

    fprintf Been here awhile

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    No horse in this race, I just wanted to say this was very interesting to read. So the only thing missing from this helpful reply is that some shops recommend a BP5HS instead of an BP5ES. According to NGK at http://www.ngk-sparkplugs.jp/english/techinfo/qa/q04/index.html the difference between the H and E is the thread reach, which I think would be kind of helpful to get right! I wonder why RYP and Splatshop recommend H instead of E?
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  4. heffergm

    heffergm Long timer

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    Manual should state which to use. I should mention:

    The P part of BRP... is 'projected', meaning projected tip. There's a non projected tip version obviously. Again, use whatever your manual calls for.
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  5. PMK

    PMK Been here awhile

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    I would be cautious of the difference between someone saying an E vs H plug. That is the thread length. E being 3/4" and H being 1/2".
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  6. Greebe

    Greebe Been here awhile

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    Thanks guys. Yeah that was what I was concerned about. Not sure how two different length plugs could both be correct for the bike. Seems like there would only be one plug that would be right for the bike.
    #6
  7. Greebe

    Greebe Been here awhile

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    BTW, the manual that came with the bike is for the older standard Scorpa Twenty model, that has the cast one piece head, not the two piece machined head with insert. Wonder if that also changes things?
    #7
  8. wheelieman14

    wheelieman14 Adventurer

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    BP5ES is "projected tip" 5 heat range with 3/4" thread length and standard thick center electrode.
    BPR5ES is same as BP5ES, but is a "Resistor" plug to help with radio interference.
    BPR5EIX is very similar to BPR5ES, except it has very thin center electrode of "Platinum?"

    I run BPR5ES on 16 Evo 125 Factory without any issues.

    I run BPR7ES on 16 Evo 300 (for some reason, the bike runs better with BPR7ES than the much more expensive BPR7EIX). My limited testing of different NGK plugs seems to indicate that the EIX version isn't any better performance-wise than the $2.00 Standard spark plug.

    BR5HS, or BP5HS, BPR5HS will only have 1/2" thread length, so ES & HS plugs aren't interchangeable.
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  9. alpineboard

    alpineboard Been here awhile

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    There is a thread on another website about this, NGK = lower # the hotter the plug spark. But go too hot and you can melt a hole in the top of your piston if you are on it a lot. But the insulator size is the key element here, on determining the heat of spark. It is either the bigger the insulator the more heat at spark or vise versa. But it is the ability of the insulator to conduct the heat away from the electrode, that determines the heat of spark.
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  10. motobene

    motobene Motoing for 46 years

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    Spark plugs, like oil, have a lot of invisible and assumed parameters and ideas swirling about. Some people swear by super-zoot unobtanium plugs, and others, like me, just run standard-type plugs.

    Perception is reality, as they say.

    The one critical aspect of the plug to pay strong attention to is its heat conductivity spec, such as 5 in NGK (lower is hotter). Heat conductivity rate is determined by the depth of the 'moat' around the ceramic tip, as in how hot the tip will get under various engine loads. The longer the thermal path from the tip back into the body, the hotter the tip can glow under a given load. Trials bikes tend to run plugs on the hotter side, though I was gobsmacked to find a 2 heat range NGK in my Yamaha generator! You want a plug that will burn stuff off its tip, but not glow so hot under max load as to melt the tip or a hole in the piston. But that is not something we worry over in trials. Not many trials bikes do max sustained load od 30 laps of speedway.

    One of my favorite plugs is the Champion RC14YC (RN instead of RC is the typical bigger hex). This is a boring hot standard-type plug, maybe like a B4 in NGK, with a 5/8" hex head so you knock off a few grams. Again, it really doesn't matter much as long as the plug isn't too cold.

    I remember in the `70s hearing stupid things like, "cold plugs start better." I'd say, "Only if your power band snaps!"
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  11. Greebe

    Greebe Been here awhile

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    So I checked the bike with the spark plug out, I am able to measure the thread in the head. It is only 1/2" long. When the piston is at TDC there is plenty of room for the longer E plug. However I wonder if more plug thread sticking out past the end of the head thread would cause fouling in that portion of threads causing more wear to the head when removing the plug, or possible a stuck plug. Maybe I will stick with the shorter BP5HS, since the bike has a Denso W16FPR-U which has the 1/2" thread. Does this sound right?
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  12. wheelieman14

    wheelieman14 Adventurer

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    Spark Plugs threads should essentially sit flush with inside edge of combustion chamber. I don't recommend installing 3/4" thread into 1/2" deep spark plug hole in cylinder head. Nor do I recommend installing a 1/2" thread into 3/4" deep spark plug hole. You are likely to cause more problems than solutions using the incorrect length spark plug.
    #12
  13. lineaway

    lineaway Long timer

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    First you can never believe anything written in a manual, especially if has been translated. Second these people are lazy, one year looks as good as another. Did you also know that everything on the internet is true?
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  14. Twin-shocker

    Twin-shocker Long timer

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    Have fitted irridium plugs to old TS bikes and tested before and after. They actually do make a difference and I would say well worth fitting even though they cost slightly more.
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  15. broncobowsher

    broncobowsher Long timer

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    I will foul out a plug, or at least get a fair bit of build up on the plug long before I "wear" one out. Now on a modern EFI car that is running right, the double iridium ultra mega hight zoot super sparky is great. They don't foul or build up deposits. They can last over 100k and still run great.
    But a carburated 2-stroke motorcycle, even well tuned and running good oil, just a regular plug. I found a deal on an 8-pack on Amazon. I have fresh spark plugs for years to come. Running slightly odd? Put a fresh plug in. $2 a piece is way better then $12+ a piece.
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  16. Twin-shocker

    Twin-shocker Long timer

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    Poorly tuned bikes running the wrong oil at inappropriate mix ratios are probably not worth fitting irridium plugs too. However on a well tuned bike using the proper oil at the right ratio they do make a noticeable difference to running. I was surprised that they make so much difference!
    #16
  17. motobene

    motobene Motoing for 46 years

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    Oh yeah I forgot about the later Sherco compacting the head design and using 1/2" reach plugs. I'm still running the Denso blabbityblah plug. I pulled it to grease the plug threads when new but otherwise don't even think about it.

    I basically never expect to have a problem with plugs. We'll jetted R-Us!

    But this reminds me that I have not one spare 1/2" reach plug other that stealing the one out of the 125.
    #17