'72 airhead coil questions

Discussion in 'Airheads' started by adventurexpress, Dec 20, 2010.

  1. adventurexpress

    adventurexpress Adventurer

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    Yet another question from a noob.

    I own a 1972 R60/5. Restored a couple of years, and now I have some electrical issues. After poking around the headlight pod, which is where the smoke came billowing out, I found some stripped/worn wires where I believe the problem started. More specifically, I believe the turn signal wires were the main culprit and then led to the internal wires of the headlight pod.

    I am taking this opportunity to upgrade my electrical components, including the coils and possibly the electronic ignition (depending on money levels). I currently have bosch 6v coils running the machine, but would like to upgrade to something such as a Dyna system including the Dyna electronic ignition.

    This is what I am looking at (12-101 & 12-100).
    http://secure.capitalcycle.com/Accessories/products/85/
    Can someone please tell me if that option will work on my bike? Or suggest a different coil and electronic ignition system for my bike? Or say something that you prefer in lieu of what I am looking at?

    Help me get my girl back on the road :wink: ...

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    #1
  2. wirewrkr

    wirewrkr the thread-killer

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    All I will say is buy elsewhere.
    The easier cheaper way is with the Dyna Booster, and a single Dyna green coil. The booster is way cheaper and pulls the load off of your points, so they don't burn. (no arcing)
    Keep in mind that the stock coils on your BMW rarely fail.
    Trust me.
    Call San Jose BMW (408-295-0205) and ask Chris (ext 14) what he thinks.
    Robert
    #2
  3. mykill

    mykill odd

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    I could not agree more. I'm even a big fan of keeping the points. Yes, they need to be adjusted every now and then, but it gives you an opportunity to check everything out. Your idle gets lumpy so you take off the front cover and adjust, while you are in there you check for leaks or burned wires, maybe you will check your valves and adjust your carbs. Electronic ignitions work great until they don't, then they are dead and so is your trip.
    #3
  4. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    I'll third that. Electronic ignition is great and works well, but when it don't work, you walk. Points, at least, can be made to work in a pinch. My major 21st century upgrade was adding a Dyna Booster-- works wonderfully, and the points don't pit and burn, although you do have to adjust the gap every so often since the rubbing block still wears. Secondary advantae is that the point dwell value is determined by the circuitry and not the point gap, so that wear is no longer as much a factor.

    I did replace my coils after 30-ish years. The hadn't failed, but back then, "we" would regularly pull a plug wire for carb balancing and to check cylinder balance without using shorting adapters. That can and will cause failure of electronic igntions, and the concensus was that it could weaken the coil internally and cause failure with points-ignition, so I did a preemptive replacement.


    BTW, nice Toaster.
    #4
  5. ducsingle

    ducsingle Been here awhile

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    If your bike has the original wiring harness, you should spend money replacing that and any sub-harnesses that are old and brittle before anything else.

    Lots of doom and gloom comments above about electronic ignitions but no apparent real-life experiences with electronic ignition failures. . . . :dunno

    I run a Boyer on my /5 and it works well. I have friends who have run Boyers on British bikes for more than two decades with no failures. The Dyna system is a little lower tech than the Boyer in that it retains the stock mechanical advance whereas the Boyer has a fully electronic ignition curve. The Boyer and Dyna systems seem to be the most popular, but other options are available.

    Motorrad Electrik sells replacement Bosch coils for about what you'll pay for the Dyna coil + bracket. I would go for the Bosch coils myself.
    #5
  6. Beemerboff

    Beemerboff Long timer

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    When I fitted a Boyer to my R75 around ten years ago I asked Boyer which coils they recommended - they replied that Dyna coils were the best they had tested, by far.

    IMHO the Boyer has a better curve than the stock unit, and the current model works equally well even if the battery voltage is down.

    I have had no trouble with the Boyers on my bikes, but I dont set my carbs by the shorting method either.
    #6
  7. Jasper ST4

    Jasper ST4 Guest

    I've had a Boyer on mine for at least 20 years, love the electronic advance, set and forget. I went back to Bosch coils, I had Dyna coils for many years but noticed that I was going through plug wires fairly quickly. I assume it was from the higher output coils so I ditched them and never had trouble again.
    #7
  8. adventurexpress

    adventurexpress Adventurer

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    Thanks for all of your responses!
    I like the concept of the dyna booster and single coil, while leaving the points alone. My question is about the single coil. Why can I run the bike 'better' using a single green coil and a dyna booster? This doesnt seem right as originally it uses dual coils to fire. Is there a an answer for dummies?

    And this is the green coil I was looking at... correct?
    http://www.motoelekt.com/ignition.htm
    #8
  9. Jasper ST4

    Jasper ST4 Guest

    I'm not familiar with the single coil, it must be 12v. The dual setup is two 6v coils wired in series.
    #9
  10. El Hombre

    El Hombre Banned

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    #10
  11. mykill

    mykill odd

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    My race bike runs a Dyna green coil, Dyna booster and points. Since BMW's run a "wasted spark" the two stock 6 volt coils are essentially the same as a dual output Dyna.
    I have Boyers on my Norton and Triumph and they work great, the closest thing to a failure was fixed by re-soldering a wire to the board after ten years of use. I feel the Boyers are a great solution to dealing with the Lucas dual points. If you still have a zener and it fails the resulting high voltage will kill the black box. BMW's charging systems do not really fail like that. My point (pun mildly intended) is that the single BMW points are easy to live with and the cash required for an electronic ignition may be better spent elsewhere and the "hands on" required by points maintenance aids in early detection of other issues.
    #11