1. After 20+ years it's time to pass the torch. If you are interested in acquiring this forum please contact support@cv-performance.com for details. Any spam will be reported and blocked.
  2. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation.

    There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.
Bike Talk Motorcycle Forum is For Sale Welcome to Bike Talk

Duel Plug vs Single Plug

Discussion in 'Motorcycle Tech Talk' started by JohnnyBiker, Jan 18, 2011.

Page 2 of 3
  1. olbill

    olbill Active Member

    Joined:
    Jan 8, 2011
    Messages:
    118
    Likes Received:
    15
    Location:
    Portland Oregon
    I believe that all depends on what the designers think the needs of the engine are. The old breaker point systems maxed out at about 35000kv the new electronic systems can stop your heart if you get a hold of it wrong.The perfect mouse trap has not been invented yet.
    olbill, Jan 20, 2011
    #21
  3. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    I can assure you it's not over engineered to put out more than needed lol

    You can buy a hotter coil aftermarket or SE, but unless you do a lot more
    it's nothing more than a wallet cleaner...
    hotroadking, Jan 20, 2011
    #22
  4. olbill

    olbill Active Member

    Joined:
    Jan 8, 2011
    Messages:
    118
    Likes Received:
    15
    Location:
    Portland Oregon
    After 43 yrs in the auto. repair business i totally agree with you. If it ain't broke don't fix it.

    olbill
    olbill, Jan 20, 2011
    #23
  5. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    Were there that many issues with the shovel heads that then required the dual plug? Sounds basically that it is essentially useless?
    JohnnyBiker, Jan 20, 2011
    #24
  6. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    you are correct johnny. i have owned a box car full of shovels.........never needed the dual plugs. i think there mostly for braggin at the ice houses.............the ones cardboard frequents..............
    chucktx, Jan 20, 2011
    #25
  7. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    yep lookit me I got dual plugs an' a kicker
    I'm cool!:roflmao:
    hotroadking, Jan 20, 2011
    #26
  8. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    It's too bad that I like the rest of the bike as well. Pretty clean ride that I am looking at that has them on.
    JohnnyBiker, Jan 20, 2011
    #27
  9. olbill

    olbill Active Member

    Joined:
    Jan 8, 2011
    Messages:
    118
    Likes Received:
    15
    Location:
    Portland Oregon
    Johnny if you like the bike go for it you can always convert it back to single plug just put a couple of 14mm proper length drain plugs in the holes and disconnect the 2nd system or if it runs strong and any body ask you about you about it you can expound on the information we all have shared with you GOOD LUCK!!!!!!!!

    olbill
    olbill, Jan 20, 2011
    #28
  10. alex the dog

    alex the dog Active Member

    Joined:
    Aug 6, 2010
    Messages:
    1,336
    Likes Received:
    0
    Location:
    Buena Vista, CO
    JohnnyBiker : Harley never put on the dual plug heads from the factory except for the XR750 racers, and those engines are pure racing design. Guys who hot-rodded their stock motors had machine shops do the dual plug heads when they were using high comp. pistons (over 10-1) and big cams. Results are only debatable.

    Today, even the high comp.- high flow heads you can buy for a Harley don't need dual plugs. But you can improve the combustion with iridium plugs (several good brands) and a high output coil (Crane or Dyna) if you build-up (pistons and cams) the motor for more hp. Don't forget to use good plug wires too.
    alex the dog, Jan 20, 2011
    #29
  11. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    i certainly would not pass on the bike for that reason.......that is crazy. dont let the dual plugs bother you. hell ya can put compression releases in the holes if ya want..........:)
    chucktx, Jan 20, 2011
    #30
  12. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    I won't. I like the idea of the compression releases though. although that could be a real pain if I was kicking the bike over vs. the starter. :D
    JohnnyBiker, Jan 20, 2011
    #31
  13. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    actually it would make it easier.........especially if ya use the automatic version........they close automatically, not manually,,,,,
    chucktx, Jan 21, 2011
    #32
  14. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    Good point dude!
    JohnnyBiker, Jan 21, 2011
    #33
  15. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    :d
    chucktx, Jan 21, 2011
    #34
  16. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    So do those auto releases only pop off when the bike is started, or when ever it turns over?
    JohnnyBiker, Jan 21, 2011
    #35
  17. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    When started they are wired into the start button circuit so when you press that button they open and when you release (engine starts) they close.
    hotroadking, Jan 21, 2011
    #36
  18. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    the only harleys with dual plugs was the flat track 750 for racing only........
    chucktx, Jan 21, 2011
    #37
  19. Lucifer

    Lucifer Well-Known Member

    Joined:
    Mar 20, 2008
    Messages:
    3,861
    Likes Received:
    102
    Location:
    Cape Breton NS,Canada
    Lucifer, Jan 21, 2011
    #38
  20. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    pretty good article, not many made, the article sorta points out why.......vibrations!
    chucktx, Jan 21, 2011
    #39
  21. mpz

    mpz Member

    Joined:
    Aug 29, 2008
    Messages:
    6
    Likes Received:
    1
    Lots of people recommend dual plugs for shovelheads because of the hemispherical combustion chambers. The flame has to make an arc to light the mixture so it's not an efficient way to burn fuel. Still makes good power, so dual plugs which light the mix at two different places in the arc make even better power and better fuel mileage as well. Modern designs, like the D shaped Evo and bathtub TC combustion chambers concentrate the mixture in a smaller area so it's much more easily and quickly lit.
    mpz, Jan 21, 2011
    #40
Page 2 of 3

Share This Page

XenPorta © Jason Axelrod from 8WAYRUN.COM