Author Topic: 1984 K100 coil options  (Read 8960 times)

Offline GaryFrank

  • Motobrick Curious
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1984 K100 coil options
« on: July 08, 2019, 06:42:31 PM »
Hi all

I'm wondering what my options are regarding ignition coils.
P.O suspected a faulty coil and tried to fit a Ford Focus coil pack (hence the burnt wires)

I've read on another forum that it does work and am asking if anyone here has tried anything similar.
I know that OEM would be the best option but am working with Monopoly money (15:1)

Thanks
  • Cape Town
  • K100 RS

Offline Scott_

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Re: 1984 K100 coil options
« Reply #1 on: July 08, 2019, 10:13:56 PM »
Unlike the K75 that uses 1 coil per cylinder, the 4 cylinder bikes utilize coils that have 2 HV outputs on each coil that both fire at the same time(wasted spark design)..... Can't say as I have heard of any auto application ignition coil that is the same configuration.....
Personally I wouldn't waste my time or limited money on something that would be a "maybe" resolution, and rather spend it on the correct OEM solution and not wonder how long it might last..... Try and find yourself a good used one, if your sure that is the issue. Depending on your problem, it could be the ignition amp that is causing issues and not a coil.... Check and make sure the heat sink paste is fresh and not dried up on the backside of the amplifier module, not uncommon as the bikes age and some owners don't think about it.
  • My Garage
1995 K1100LT 0302044
1997 R1100RT ZC62149
2017 FLHTK Ultra Limited
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Offline The Mighty Gryphon

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Re: 1984 K100 coil options
« Reply #2 on: July 09, 2019, 09:59:08 AM »
I agree with Scott that getting the correct coil is the way to go.  The early coils had issues that were corrected in later units.  If you can find used K100 coils from an '87 or later you should be in good shape. 

In the years I have been hanging around these forums I've seen a fair number of riders change out those old coils for the newer design with excellent results.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline JPaganel

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Re: 1984 K100 coil options
« Reply #3 on: July 10, 2019, 12:53:43 AM »
Unlike the K75 that uses 1 coil per cylinder, the 4 cylinder bikes utilize coils that have 2 HV outputs on each coil that both fire at the same time(wasted spark design)..... Can't say as I have heard of any auto application ignition coil that is the same configuration.....

Lots of automotive 4-cylinders do it. GM for sure. But the coils are usually in an inconvenient large plastic box.
  • Minnesnowta
  • 1986 K100RT, 1996 R1100RS

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #4 on: July 25, 2019, 03:11:37 PM »
Okay, so I’ve replaced all the burnt wire and fired her up.
Missing on number 3 plug. Switched 2 & 3 plug wires On the coil and the miss moves to plug 2.
Coil is definitely toast but the replacement cost is stupid.

This leads me to an alternative- Ford Focus also fires 1 & 4 (wasted spark)
The only possible problem I can see is that the Ford unit has a low impedance - 1,2 ohms.
Will this eventually kill my ignition unit ?
Are there any options as in firing an in-line amplifier ( or summat to that effect)???
  • Cape Town
  • K100 RS

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #5 on: July 25, 2019, 03:17:15 PM »
Said Ford coil....
  • Cape Town
  • K100 RS

Offline daveson

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Re: 1984 K100 coil options
« Reply #6 on: July 25, 2019, 03:50:49 PM »
The problem followed the wire,  hopefully the coil is good and it's only a bad wire.
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #7 on: July 25, 2019, 03:52:12 PM »
Nah, not so lucky..... it’s definitely the coil
  • Cape Town
  • K100 RS

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #8 on: July 25, 2019, 04:12:28 PM »
From our friends at Summit Racing:


“So, less resistance is better, right? No. Not always.

If the resistance is too low, the added current could damage the distributor points or the electronic ignition module. When shopping for a coil, make sure the primary resistance is compatible with your other ignition components.”

Has anyone come up with a solution.....in-line amp of sorts
  • Cape Town
  • K100 RS

Offline Laitch

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Re: 1984 K100 coil options
« Reply #9 on: July 25, 2019, 04:24:27 PM »
Missing on number 3 plug. Switched 2 & 3 plug wires On the coil and the miss moves to plug 2.
Did you inspect the faulty terminal coils terminal for corrosion?
I've read on another forum that it does work and am asking if anyone here has tried anything similar.
What was used for a successful coil substitute in the post on other forum?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #10 on: July 25, 2019, 04:39:37 PM »
I did inspect the coil in every direction ( this was the original problem which led to the PO’s diy wiring burn-out)

Other site mentioned a Ford Mondeo coil pack and stated that it works, but makes no mention of leaks no term effects. I have also spoken to a local (South Africa) who has run on the Ford coil but changed back to original...

I will wire up the Ford coil tomorrow just to run her on all 4, but will keep on digging till I find a cheaper solution.
  • Cape Town
  • K100 RS

Offline daveson

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Re: 1984 K100 coil options
« Reply #11 on: July 25, 2019, 04:47:59 PM »
How did you decide it's not the wire?  Are all four wires the same brand and type?
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #12 on: July 25, 2019, 04:53:10 PM »
Sorry, I didn’t mention that I had partially rewired the bike.
All the coil wires, right handlebar switch, ignition switch, front brake switch.....
I’m still looking for a right handlebar switch - have “hotwired” everything needed to get her running
  • Cape Town
  • K100 RS

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #13 on: July 25, 2019, 04:54:57 PM »
Plug leads are brand new
  • Cape Town
  • K100 RS

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #14 on: July 25, 2019, 04:58:32 PM »
I did inspect the coil in every direction ( this was the original problem which led to the PO’s diy wiring burn-out)

Other site mentioned a Ford Mondeo coil pack and stated that it works, but makes no mention of LONG term effects. I have also spoken to a local (South Africa) who has run on the Ford coil but changed back to original...

I will wire up the Ford coil tomorrow just to run her on all 4, but will keep on digging till I find a cheaper solution.
  • Cape Town
  • K100 RS

Offline daveson

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Re: 1984 K100 coil options
« Reply #15 on: July 25, 2019, 05:04:25 PM »
It's rare, but sometimes new stuff is faulty,  which mondeo engine and year have you used.?

Let us know the results if you end up running with the mondeo coils.
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #16 on: July 25, 2019, 05:14:51 PM »
Will play some more tomorrow.
I have no doubts about the Ford coil pack working, I’m just concerned about the long term effect (1,2 ohm coil resistance)
  • Cape Town
  • K100 RS

Offline The Mighty Gryphon

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Re: 1984 K100 coil options
« Reply #17 on: July 25, 2019, 10:03:16 PM »
I wonder what the availability of used later model K100 coils is like in S.A.  That is  the route I would go.  Early coils had problems, later model coils are a lot more reliable.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline johnny

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Re: 1984 K100 coil options
« Reply #18 on: July 25, 2019, 10:15:43 PM »
greetings...

there is a bike breaker in south africa that has brick parts...

there was a motobricker here a few years ago from south africa and chronicled his drama scoring parts...

i will have to think about it later because im exhausted from unwhacking tommyts whack...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny
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Offline Laitch

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Re: 1984 K100 coil options
« Reply #19 on: July 25, 2019, 10:25:28 PM »
Will play some more tomorrow.
I have no doubts about the Ford coil pack working, I’m just concerned about the long term effect (1,2 ohm coil resistance)
It could overheat the electronic control unit resulting in its failure but there might be used control units available, maybe at the bike breaker j o has indicated.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #20 on: July 26, 2019, 04:03:54 AM »
I found a pair of orange tops on eBay for GBP30. Number 2 son is getting them for me 👏👏👏

Still gonna connect the Ford unit just to fire her up and check everything, then I’ll strip her down and make pretty. 
  • Cape Town
  • K100 RS

Offline daveson

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Re: 1984 K100 coil options
« Reply #21 on: July 26, 2019, 04:38:06 AM »
Do you want to use Focus coils like the PO did?
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline GaryFrank

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Re: 1984 K100 coil options
« Reply #22 on: July 26, 2019, 04:39:50 AM »
I don’t think he knew what he was doing - electrickery isn’t for everyone
  • Cape Town
  • K100 RS

Offline daveson

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Re: 1984 K100 coil options
« Reply #23 on: July 26, 2019, 04:40:55 AM »
"P.O suspected a faulty coil and tried to fit a Ford Focus coil pack (hence the burnt wires)"

In reply #4 you say you want to put Focus coils in.

Huh ...hang on...  wait...  what?

Am I missing something?
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline daveson

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Re: 1984 K100 coil options
« Reply #24 on: July 26, 2019, 04:45:06 AM »
Oh, OK.

I'm wondering why the other bloke who tried them went back to the originals.

Somehow I can't attach quotes properly anymore,  it just turned into multiple posts.

Anyway let us know the results please.
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

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