BMW K bikes (Bricks)

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1Back to top Go down   Aftermarket coils - utopia? Empty Aftermarket coils - utopia? on Fri Aug 09, 2013 5:20 am

Erman

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Not trying to be a pioneer here, but as we know all OEM parts for the K's are an expensive deal. 
The idea is to discuss and possibly find viable (read cheap) aftermarket coils. The motivation behind this, is that I've successfully upgraded the coils on my Seca to ones from Dyna, with almost 50% savings compared to OEM.

What's weird about the coils, is that BMW do not provide any resistance values. Haynes says N/A on the dual coils, and Clymer claims BMW do not provide testing procedures or resistance values. It's almost as if BMW knew they were into some black magic and didn't want others to know. 
In this post, Rick says the HT coil shoud measure 40k Ohms: 
https://www.k100-forum.com/t4798-it-s-not-the-alternator-it-is-the-2-3-coil?highlight=coil
Other properties of the OEM coils, are the mounting mechanism and three wire system (+/- and signal), firing order: 1-3-4-2, and I'm assuming 3 Ohm primary coil resistance. The firing order is probably what makes the coils need three-wire setup, but it also effectively disqualifies a lot of aftermarket coils.

Here is the price list for OEM material:

- Ebay (used): from 40$
- Motobins: 134,50£
- Motorworks (used): 38£
- Motorworks (new): 103,20£


Presumed applicable aftermarket candidates:
NONE


Why, oh why, BMW????


__________________________________________________
Bikes:

1984 BMW K1000RS

1984 Yamaha XJ750 Seca
    

2Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 6:34 am

RicK G

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"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

3Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 7:20 am

charlie99

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more than a few of us have measured good coils

we all find that the secondary is about 10.6 k on good working ones


yes about 3 odd ohms for the primary coil


there are others around with metal cores and that could be mounted to the frame to do the same thing ....which helps eliminate spikes into the electrical system,

just wont look the same

but I cant think of many automotive ignition systems that use double fire coil packs as a general rule of thumb .

most use single coil and a distributor type system ...or the more modern ones are now usually coil on top of each plug.
although some of the Kawasaki Vulcan machines use double fire coils (2 plugs one cylinder x 2 )  so there is hope


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OAftermarket coils - utopia? Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

4Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 9:35 am

Guest

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I can think of two double fire coil applications, the first would be the 2 stroke Rotax 582, but I would think that would be very expensive. The second would be a Citroen 2CV, which would be very cheap. Not sure if either is suitable for a K.

    

5Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 10:15 am

92KK 84WW Olaf

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bikerboy wrote:I can think of two double fire coil applications, the first would be the 2 stroke Rotax 582, but I would think that would be very expensive. The second would be a Citroen 2CV, which would be very cheap. Not sure if either is suitable for a K.
Last time I was down your way I noticed quite a few Citroen 2CV and Renault 4 cars happily living extended lives. Does the 2CV use a distributor though? The K uses the wasted spark on the 4 cylinder machines which makes me wonder could a coil from a 2 stroke engine produce the required spark?


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 105,200 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

6Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 11:51 am

Guest

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The 2CV has no distributor and is a 2 cylinder 4 stroke. The points fire the coil which has two HT leads and works also on the wasted spark system.
The Rotax 582 also has two HT leads on one coil.
Link to 2cv coil http://www.franzose.de/en/Citroen-2CV/Dyane/Zuendung/ANR14311/ .

    

7Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 2:29 pm

charlie99

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seams  Harley  have a similar type dual fire setup

Aftermarket coils - utopia? $T2eC16NHJHEE9ny2qTM3BRMUI6Km2g~~60_14

 and about the right primary coil measurements of 3 ohms .....well on the ones I saw


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OAftermarket coils - utopia? Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

8Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Fri Aug 09, 2013 3:24 pm

Erman

Erman
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I just did a multimeter check on the primary coils and got 4,3 Ohms. The secondary coils yielded no results...


__________________________________________________
Bikes:

1984 BMW K1000RS

1984 Yamaha XJ750 Seca
    

9Back to top Go down   Aftermarket coils - utopia? Empty Re: Aftermarket coils - utopia? on Sat Aug 10, 2013 12:58 am

Ghost who rides

Ghost who rides
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Most Japanese bike four cylinder use similar coils dual ht s and wasted spark, nothing special there but still maybe expensive? they are also small and i've never heard any complaints about reliability or performance, should be cheap and a safe bet buying 2nd hand. Just up to you electro boffins to determine if the ohms work out? Am I right in thinking that the ICU does'nt give a toss about that? It's only to give a fat short spark? If so use leads to suit the coils?


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1986  K 75 C   2nd owner 187,000kms showing .
1987  K100RT  Police repainted, rough and unloved.
    

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