coil wiring ,,

Discussion in 'Airheads' started by trabbart, Mar 16, 2013.

  1. trabbart

    trabbart hellrider

    Joined:
    Mar 8, 2013
    Oddometer:
    47
    i removed my 2 coils and i think forgot how they where wired :huh
    i have one green./blue wire, a bridge in black wire, a black wire from under the front cover, and a black wire comming out of the harnas.
    that last one i cant remember.
    one coil needs the green blue, and the black bridge going from that coil to the other, but the two blacks(the one from the harnas and the one from the cover) ? are they both on the same terminal at the second coil? like my misirable drawning

    [​IMG]
    #1
  2. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

    Joined:
    Sep 29, 2010
    Oddometer:
    4,351
    Location:
    Big Island of Hawaii
    Here is the basic wiring: [​IMG]Not sure about the extra black wire coming from under the cover, but the one from the harness on my '74 R75/6 is from the points as shown in this picture from Duanes website. Do you have an add on electronic ignition?
    #2
  3. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    10,412
    Location:
    Silver Spring, Md
    BB's wiring diagram is correct.

    The extra black wire? Does it have a female plastic terminal on it? I forget what it was for but you most likely don't have it.
    #3
  4. trabbart

    trabbart hellrider

    Joined:
    Mar 8, 2013
    Oddometer:
    47
    i dont know if i have points or wathever. it started always easy untill i started working on it. i replaced the muflers for open pipes, tank on and off etc etc .
    all kind off stuff,,upgrade egnition was my plan after all the other stuff but ,,now it started verry hard and i noticed on one cilinder. one exhaust was getting hot while the other remane almost cold. i removed the plugs , plugwires and coils but came up with more wires than i thougt and i am sure they where connected
    i still have the 30 year old coils and have now ordered new ones , new cables and plugs. untill they are delivered i can not try.

    i open up the cover and try to see where the black wire is going to,,i suspect it goes to the points or wathever. i will picture it later...
    #4
  5. trabbart

    trabbart hellrider

    Joined:
    Mar 8, 2013
    Oddometer:
    47
    its a 1980 bike 100rs
    i have 12v between the blue green and the black with plastic terminal from out of the harnas.(with egnition on)
    the one going into the front cover i suspect is going to the egnition trigger.point or elecktronic.
    with my diagram the coils are always under voltage????

    i dont want to mess with the timing now,,i dont open that up untill the bike is running again. the bad sparks are comming from them old coils and wires, and i want to fix that first before messing with timing and points who where fine before. one step at the time with that part of the bike or i will be pulling my hair out
    #5
  6. Plaka

    Plaka Brevis illi vita est

    Joined:
    Jun 19, 2010
    Oddometer:
    4,615
    Look at the wiring diagram in your manual. (hint: tachometer)
    #6
  7. 190e

    190e Been here awhile

    Joined:
    Feb 20, 2013
    Oddometer:
    880
    The correct wiring will ensure the most efficient spark polarity.[​IMG]
    #7
  8. trabbart

    trabbart hellrider

    Joined:
    Mar 8, 2013
    Oddometer:
    47
    great thanks,,,i could not find that in the manual , now i am sure.

    hope to get the new coils, plugs and wires soon.
    #8
  9. Bill Harris

    Bill Harris Confirmed Curmudgeon

    Joined:
    Sep 20, 2008
    Oddometer:
    8,718
    Location:
    backwoods Alabama
    If you are going to the trouble of replacing coils and plug wires (ie, throwing money at the problem) the first thing you ought to do is check and replace the points.

    --Bill
    #9
  10. trabbart

    trabbart hellrider

    Joined:
    Mar 8, 2013
    Oddometer:
    47
    i replace the 30 year old coils anyway,,even iff they still work , replacing and adjusting the points will be done after i am sure i have good parts everywhere else. everybody replaces the points because there cheap,,the coils stay on the bike untill they fail, but the spark can be a lot hotter with new coils ,,save you lots of troubles, gas and bad starting etc etc
    #10
  11. Plaka

    Plaka Brevis illi vita est

    Joined:
    Jun 19, 2010
    Oddometer:
    4,615
    UM..coils don't wear out. They break (internal short or open) and they can break and still make a spark, albeit a weak one. They get crudded up contacts which can be cleaned. So you test a coil and if it's making a nice fat spark, it's fine. If you do replace it, then get a better one, the most your points can handle (use a booster to run really hot coils). Little point spending money on a stock coil. if you can find 6 volt Bosch Blue coils they'll run with stock points and fit the stock brackets. Real nice sparks.

    points wear out. The contacts get pitted (real fast if they aren't super clean) and the rubbing block wears down. Back in the day we used to file points and you still can in a pinch. But if they are good they are good.

    The spark plug wires get tested and replaced if the resistance is too high...or if they're ugly.

    Condensers wear out. Get a big one and it lasts forever.

    The rest of the wiring is your real problem. You can't throw money at it, you just have to go over each connection and make it beauteous. Adding some extra grounds a few places helps too.

    The place to spend more and sooner is the battery. And fresh plugs.
    #11