Hell All,

I have found that I have a dead ignition coil, which was causing all sorts of driveability problems that came and went. The bike would run on all cylinders when cold, then would lose cylinder #4 as it warmed up and would lose #4 and #1 once it got fully hot.

In reading some of the excellent posts on this forum, I have ordered a pair of "orange tower" coils from a later K100. These have a BOSCH two pin connector instead of the typical open 5 mm male spade connectors as my '85 K100 has...

So, I will have to source a proper BOSCH two pin female connector to make this work. The two questions are:

1) Does anyone have a source (i.e. Dorman, etc.) for a pigtail with this female two pin form factor?

2) Has anyone done this so as to be able to advise me about which color wire goes where? 

Thanks for whatever anyone can contribute

If they are a 2 pin connector they are K1100. I would advise you don't use them as you would be taking a chance of damaging the ignition control unit (ICU). The primary windings of the K1100 coils are a lower impedance than the K100 and too much current could easily fry the output transistors in the ICU.
They may be from a K100RS 4 Valve but the same applies.

Here is the connector style. So these are for a K1100 and can't be adapted to an '85 K100?

The seller says they came off of a '92 K100 4 Valve. Maybe that's the difference.

If I have to find the open male spade connector orange tower coils, has anyone found a good source or a "will-fit" from some supplier? These are crazy expensive -

Yep that's the K1100 type.
You can see the two coils at the bottom of this page to tell the difference
http://www.euromotoelectrics.com/category-s/795.htm

What RickG said. These are not for 8V K100, 1983 through about 1992. These fit later models of K100-16V & K1100. Avoid at your ICU's eventual peril.

Many of the people don't realize just how different the 4v is to a 2v

Great, guys. Thanks for the input. 

Are there any alternative to the $169 coils from Euro Motoelectrics? 

I'm not against capitalism, but Bosch coils for my '91 Porsche were $50 and in researching them I found a myriad of coils that would work as "will-fits" without damaging the ICU/ECU. At some point it is a simple step up transformer with a given primary coil resistance that is compatible with the ICU trigger circuit. 

Somewhere there is a Bosch or Beru engineer who would tell us to "just make sure X is no less than Y" with regards to the specific needs of the ICU drivers and the coil's primary side's specifications and we'd have a compatible cross over coil for a two cylinder wasted spark system...

eBay K100-8V coils

Some times you get lucky. Some times you don't.

TWB

Great tip - thanks for sending it along. I was able to find an orange-top coil on fleabay with the correct male spade terminals  just before you sent your post. 

I am hoping that the forum postings that state that the orange-top coils are more robust will offset the risk of getting used coils. Since I'm only getting one, I'm sure my second coil will die on me one rainy night, so maybe I should buy the one you sent along as a spare (cheaper than a tow).

Considering the price of a lot of the new stuff I have built up a good stock of the electrical bits and pieces over the years.
Whatever I have left over when I get carted away to the home for the permanently bewildered will be worth more than I paid for it.

Update:

I purchased a used orange top coil on ebay and all is good now. Coil cost $42 delivered. This coil is the 2-3 cylinder unit, not the 1-4 coil that I needed, so I will have to drill out the rivets on the mounting bracket and move my old bracket over so the cover screws line up. 

Bike runs like a million bucks now - much better performance all around, even better than when all four cylinders were firing on the weak coil.

Thanks for everyone's input...

There's nothing quite like a definitive fix.
Goodonya.