1. Some members were not receiving emails sent from XJbikes.com. For example: "Forgot your password?" function to reset your password would not send email to some members. I believe this has been resolved now. Please use "Contact Us" form (see page footer link) if you still have email issues. SnoSheriff

    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.

Resistor Plugs?

Discussion in 'XJ Technical Chat' started by lorne317, Jun 28, 2008.

  1. lorne317

    lorne317 Member

    Messages:
    121
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Beaverbank,Nova Scotia
    I've had some running problems on my recently purchased 83 XJ650,so I figured I'd replace the plugs as one of my first steps.A quick search told me to use BP7ES plugs,but when I pulled mine(definitely in need of replacement) I found that they were BP7RES with the R indicating that they are a "Resistor" plug.Since I like to keep as close to the manual as possible,I bought BP7ES only to find that they don't fit.They are a fair bit longer,so the plug wrench in my tool kit doesn't work and the top part is a bit bigger so the cap doesn't fit on.Are there any up/downsides to using these resistor plugs?
     
  2. Altus

    Altus Active Member

    Messages:
    1,489
    Likes Received:
    4
    Trophy Points:
    38
    Location:
    London, Ontario
    BP7ES and BPR7ES are the identical plugs, just one has a resistor in it. And I mean physically IDENTICAL - the only way to tell them apart is that R printed on one. If yours are different sizes, then they're different plugs - no two ways about it.

    As for using the resistor plugs, it depends on what plug caps your using actually. The stock plug caps had resistors in them - 5k outers and 10k inners -- So you didn't need any resistor in the plug. Adding another 5k resistance is just weakening the already iffy ignition system further if you have both.
    If you have non-resistor caps, then no - there's no problem running resistor plugs.
     
  3. leadboots

    leadboots Member

    Messages:
    217
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    aylmer ontario canada
    my bike ran alot better with bp7es then the bpr7es
     
  4. lorne317

    lorne317 Member

    Messages:
    121
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Beaverbank,Nova Scotia
    There actually is quite a size difference.I'll try to get a pic up if I can.How can I tell if I have resistor caps ?
     
  5. bstig60

    bstig60 Member

    Messages:
    214
    Likes Received:
    1
    Trophy Points:
    18
    Location:
    Sharpes, Florida
    If the caps are factory, they are probably resistor. I changed out mine to automotive type with copper wire inside and use resistor plugs.
     
  6. Robert

    Robert Active Member

    Messages:
    7,479
    Likes Received:
    9
    Trophy Points:
    38
    Location:
    Ventura CA
    Use a multimeter and ohm them out. Taken off of the secondary high tension lead first of course. You should see 5K on the outboard units and about 11K on the inboard units (Haynes manual). If they are 1K units (common replacement units) you should run the R type plugs.
     
  7. MiCarl

    MiCarl Active Member

    Messages:
    4,373
    Likes Received:
    23
    Trophy Points:
    38
    Location:
    Livonia, MI (Metro Detroit)
    New plugs come with an adapter nipple (I don't know the proper name) threaded on top of the spark plug. This makes it fit an automotive style plug cap.

    You need to screw the adapters off so your plug cap can lock onto the stud on the top of the plug.
     
  8. wizard

    wizard Active Member

    Messages:
    5,282
    Likes Received:
    26
    Trophy Points:
    38
    Location:
    DEVON ENGLAND
    They always come (with the plug) loose in the box though !!
     
  9. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    i've seen them come attached and don't screw off but they were car plugs
    resistor plugs and wires are for radio interference, forget about them
     
  10. MiCarl

    MiCarl Active Member

    Messages:
    4,373
    Likes Received:
    23
    Trophy Points:
    38
    Location:
    Livonia, MI (Metro Detroit)
    I usually find them screwed on. Perhaps delivery south of the equator causes them to unscrew in transit.........
     
  11. wizard

    wizard Active Member

    Messages:
    5,282
    Likes Received:
    26
    Trophy Points:
    38
    Location:
    DEVON ENGLAND
    I usually find them screwed on. Perhaps delivery south of the equator causes them to unscrew in transit.........[/quote]

    nasty dose of sarcasm there. I spent the first 55 years in the Northern hemisphere, & they were always loose.
     
  12. lorne317

    lorne317 Member

    Messages:
    121
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Beaverbank,Nova Scotia
    Now I feel really stupid asking this,but are there 2 different types of BP7ES? I just bought them off the shelf at the local autoparts store.
     
  13. RickCoMatic

    RickCoMatic Well-Known Member

    Messages:
    13,843
    Likes Received:
    66
    Trophy Points:
    48
    Location:
    Massachusetts, Billerica
    I run Champions.

    I have to grab-on to the attached ends with pliers and remove the screwed-on automotive tip.

    I used to save them for some stupid reason.
    Then I took 'em all and threaded them on to an extra-large rubber band.
    Looked like jewelery.
    I finally threw that out too.
     
  14. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    don't feel bad because of me, 'cause i say some stupid stuff :)
    a bp7es is a NGK number, there are other manufacturers that make the same plug but use their own number, so i guess the answer is yes and no
    the ones that don't have screw off caps were for a ford ranger, don't know the number but i think they were autolite plugs
    the resistor plugs and wires are for the benefit of car radios and tv antennas
    turn on a am radio in the garage with a bike with real copper wires, you'll see what i mean
     
  15. lorne317

    lorne317 Member

    Messages:
    121
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Beaverbank,Nova Scotia
    I took back the first set I bought,and this time I went to the parts counter and asked for plugs to fit my bike.They gave me what appeared to be the exact same plug,except the resistor caps screw off of these ones.Thanks for your help guys.Another lesson learned.
     

Share This Page