1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

BP7ES spark plugs

Discussion in 'XJ Technical Chat' started by wkxj, Dec 27, 2021.

  1. wkxj

    wkxj Member

    Messages:
    115
    Likes Received:
    6
    Trophy Points:
    18
    Location:
    nm
    I s anyone else having trouble finding NGK BP7ES plugs?
     
  2. Noahsxj

    Noahsxj Active Member

    Messages:
    200
    Likes Received:
    105
    Trophy Points:
    43
    Location:
    SW Missouri
  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

    Messages:
    8,866
    Likes Received:
    1,780
    Trophy Points:
    113
    Location:
    The room where it happened
    The only issue with that version of the BP7ES plug (the #2412 version) is that they have a fixed (non-removable) terminal nut, which will not fit inside the NGK plug caps. The original BP7ES ---- with the removable cap nut ---- caries a different NGK part number. Believe it or not, NGK has many different part number "versions" of many of their spark plugs, all with minor (or meaningful) differences from each other. Why this is done is beyond me, but I'm sure there's a legitimate reason for doing so.....
     
  4. Noahsxj

    Noahsxj Active Member

    Messages:
    200
    Likes Received:
    105
    Trophy Points:
    43
    Location:
    SW Missouri
    All these ones remove easily!
    @chacal
    4148F60C-CA9C-4A9C-9703-90FB68E634E0.jpeg
     
  5. wkxj

    wkxj Member

    Messages:
    115
    Likes Received:
    6
    Trophy Points:
    18
    Location:
    nm
    Thanks, I ordered some. I'll see if they will work. It says fixed top nut in the description but they may be different.
    I think NGK might have discontinued the ones we usually use in our bikes. I think a certain country was making fake NGK's but they may work fine.
    edit- Okay I looked at the NGK website and they say use they BPR7ES. I am getting in touch with them to see about the fact that these are resistor plugs' I'll get back ASAP with what they have to say
     
    Last edited: Dec 27, 2021
  6. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

    Messages:
    8,866
    Likes Received:
    1,780
    Trophy Points:
    113
    Location:
    The room where it happened
    Noahsxj.....well that it odd, the 2412's should have the fixed cap (that's straight from NGK themselves) but who knows what's really going on. Thanks for the update!

    wkxj: the "replacement" BPR7ES plugs are resistive (5K ohms) so it present an issue with using the original (ore replacement) resistive plug caps, as it doubles the specified resistance specs for many of the bikes; however, it may (or may not) really make much of a difference in performance.
     
  7. Minimutly

    Minimutly Well-Known Member

    Messages:
    1,746
    Likes Received:
    748
    Trophy Points:
    113
    Location:
    West Wales, uk
    Maybe specs have changed over time, and certainly manufacturing costs would be lower for non screw cap items.
    I wouldn't use resistor plugs with resistor caps, simply because higher resistance will cause the ht voltage to get higher before the spark jumps. This could break down the tci output stage. I stress "could", but of course we have loads of cheap, spare tci's around - don't we?
     
  8. Noahsxj

    Noahsxj Active Member

    Messages:
    200
    Likes Received:
    105
    Trophy Points:
    43
    Location:
    SW Missouri
    I did visually compare the 22+ year old plug that came out of my virago with the one I ordered from this eBay seller

    they seemed identical, although I did not check resistance or ohms

    I still have them, I’ll test them both when I get home work

    if they are fake, and from this certain country you’re pertaining to, then I must say they are of very high quality!
     
  9. wkxj

    wkxj Member

    Messages:
    115
    Likes Received:
    6
    Trophy Points:
    18
    Location:
    nm
    I've been using NGK BP7ES plugs on a 82 Yamaha 650 Seca. I noticed these plugs are being discontinued and replaced with BPR7ES that I believe are a resistor type plug? My concern is that the plug wires caps are also a resistor type and might effect the control unit or the performance of the bike.
    Thanks Will


    Hello,

    Thank you for your inquiry. If your bike has electronic ignition and not points and condenser using magneto system, the resistor plugs will be fine with no issues. The only other option would be a non-resistor racing series plug, R5671A-7. The difference is the hex is smaller (13/16” down to 5/8”) and the center electrode projection (center electrode depth into the combustion chamber) is shorter. BP7ES is 3mm and racing plug is 1mm.


    So here's what I asked and their response.
     
  10. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

    Messages:
    1,177
    Likes Received:
    568
    Trophy Points:
    113
    Location:
    Minneapolis, MN
    According to NGK's cross reference material, there are several possible replacements for BP7ES from other manufacturers:
    https://ngksparkplugs.com/wp-content/uploads/2020/10/Spark-Plug-Cross-Reference_2019.pdf

    In my opinion, it is probably a better idea to convert to resistor plugs and a non-resistive cap (so just a boot, in that case?).

    Therefore, the challenge is going to be finding a cap/boot that looks "correct" and will swap out without having to splice plug wires or replace the entire coil or anything drastic like that.

    Does anybody have some good ideas for non-resistive replacement caps/boots that will work? @chacal ?
     
  11. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

    Messages:
    1,177
    Likes Received:
    568
    Trophy Points:
    113
    Location:
    Minneapolis, MN
    Also, I may be crazy, but I seem to remember somebody talking about removing the resistors from the caps? Maybe it was on the "what did you do to your Yamaha today" thread??

    Seems like some pretty major surgery considering the caps seem to be a pretty solid molded piece of plastic. I would like to see a how-to if somebody has done it.

    I may have a bad cap I could experiment with also. If I get anywhere I will share the results.
     
  12. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    The longer (inner) caps on the XJ750 Seca had replaceable / removable resistors. The outer caps did not

    upload_2021-12-28_14-19-0.png
     
  13. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

    Messages:
    1,177
    Likes Received:
    568
    Trophy Points:
    113
    Location:
    Minneapolis, MN
    OK, I see. I did cut open an NGK cap that tested bad and found the resistor in there. Definitely not going to be doing that to remove the resistor in any feasible way.
     
  14. Huntchuks

    Huntchuks Well-Known Member

    Messages:
    951
    Likes Received:
    395
    Trophy Points:
    63
    Location:
    East Rochester, NY
    My caps just need a flat head screwdriver to unscrew the sparkplug gripper/resister stopper. Be careful to not lose the little flat disk.
     
    chacal likes this.
  15. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

    Messages:
    8,866
    Likes Received:
    1,780
    Trophy Points:
    113
    Location:
    The room where it happened
    Rooster, is there a technical name for that style fuse?
     
  16. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    Resistor, special :)
     
  17. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    The original caps had replaceable resistors. They can be removed and brass rod (cut to the proper length) used. Alternatively NGK sells non-resistor caps.
     
  18. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    A look on the NGK website shows that the BK7ES is in process of being superseded. That means there will be a new plug with the required non-resistance spec under a new part number.

    A look on Amazon returns this
    https://www.amazon.com/NGK-BPR7ES-SOLID-Standard-Spark/dp/B01DMFHL5Q/ref=sr_1_1?crid=3EC9H9RVQR10V&keywords=NGK+BP7es&qid=1640730977&sprefix=ngk+bp7es,aps,83&sr=8-1

    What seems to be a like-spec plug with modern features.
    I'll do some more digging to confirm that when I have time.

    Whatever you do, don't pay scalper prices for a BP7ES. There are a lot of profiteers out there who want to make us panic-buy when there is no need to.
     
  19. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    It's just a normal carbon resistor without any wire embedded into it. I seem to recall that you had some in stock. I doubt that anyone is making them anymore.
     
  20. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

    Messages:
    1,177
    Likes Received:
    568
    Trophy Points:
    113
    Location:
    Minneapolis, MN
    On a completely unrelated subject, who needs some toilet paper?
     
    k-moe likes this.

Share This Page