I have been building a bike over the last 3.5 years. The bike was running when I pulled it apart (sorry to the purists out there) and I assumed if I packed everything away in a dry safe place it would run when I put it back together. Unfortunately it didn’t start. Fuel is pumping, engine turning, lights are on but no one is home. 

So I googled “how to test k100 coils” and read some posts on here and it doesn’t look good. But I’m afraid I don’t have a functioning coil to compare against. and worst of all I’m not having any luck with the spark plug leads either. 

If any one can shed some light and help me figure this out I feel I’m so close to getting the bike on the road!!!
FYI good second hand parts are hard to come by down here in New Zealand. So the odds are I’ll need to buy in from overseas. So really need to be sure before I “invest”. 

Thanks in advance

Clintinz wrote: So I googled “how to test k100 coils” and read some posts on here and it doesn’t look good. But I’m afraid I don’t have a functioning coil to compare against.

Having a functioning coil for comparison is unnecessary. The troubleshooting guide in the Tech Page shows typical acceptable values.

For the secondaries test, set the meter to 2000 and try again.

Clintinz,
    It's highly unlikely that two functioning coils would both die from sitting in a box for a while. Some more details of what's going on might be helpful. I assume that you're testing the coils because of lack of spark. Is the problem on all four cylinders?

   If it's just on 1 and 3 or on 2 and 4, that could be a bad coil. Easy to test by swapping the coils and seeing if the problem switches cylinders.

   If you're not getting spark on any cylinders, it could be both coils are bad but I'd say the problem is more likely upstream of that, in your ignition control computer or one of the sensors providing input to it. Have you checked your hall sensor? That would be the first thing I looked at.

   Laitch is right about changing the setting on your meter to check your secondary coil, but I disagree with the statement that you can fully test the coils with spares. You can get perfect resistance readings from a coil and still have it not work under load. For instance, if you have a crack in the casing the secondary coil can short to the frame of your bike and thus not give you a good spark. Swapping in a spare (if you have it) is the definitive test.

    If both of your coils really have failed and you can't find original replacements, aftermarket coils work great. I've been running Dynatek DC1-1 coils in my K100 for thousands of miles and they work great.

     -Jon

try new plugs first

Can you say what the bike is? 2v or 4v.

What of side stand switch [but if fuel pump is priming igniore this] clutch switch, neutral light?

Thanks everyone for your replies. To answer a few questions in one. Its a 1986 k100rs 2v. Side stand switch has been removed and clutch switch disabled for now while testing. @laitch I tried the metre at 2000 with the same results.
@bikesmith - no sparks at all. So first I tested the coils and given the lack of results on the metre I thought it has to be them. But I’ll try digging deeper. Not really sure what I’m looking for in the hall sensor or ignition control unit but I’ll google it.

I’ll try the metre again on ‘000s for the secondaries but just to double check. It only needs to be touching the copper inside and it doesn’t matter what probes go where? And should I be getting some results on the leads?
Can they be tested professionally?

Clintinz wrote:Thanks everyone for your replies. To answer a few questions in one. Its a 1986 k100rs 2v. Side stand switch has been removed and clutch switch disabled for now while testing. @laitch I tried the metre at 2000 with the same results.
@bikesmith - no sparks at all. So first I tested the coils and given the lack of results on the metre I thought it has to be them. But I’ll try digging deeper. Not really sure what I’m looking for in the hall sensor or ignition control unit  but I’ll google it.

I’ll try the metre again on ‘000s for the secondaries but just to double check. It only needs to be touching the copper inside and it doesn’t matter what probes go where? And should I be getting some results on the leads?
Can they be tested professionally?

Being a 2v it never had a side stand switch so just wondering what you did here.

How did you disable the clutch switch? The clutch switch and the two brake switches are same parts, same connectors in the loom, easy to get the wrong one.

92KK 84WW Olaf wrote:How did you disable the clutch switch? The clutch switch and the two brake switches are same parts, same connectors in the loom, easy to get the wrong one.

The bike definitely had a side stand switch but I’ve Completely rebuilt the bike and put in mo.unit blue so wiring is new (and a possible cause of issues) but I’ve been testing all the way. Everything except ignition as that was last of all.

Clintinz,
    The fact that you're using the mo.unit is 100% key to what's going on. All the advice everyone has been giving you is based on the assumption that you had stock electronics.

    I have no idea if the mo.unit is compatible with the stock k100 coils. Generally, the key is to use coils with resistance in the primary that matches what your ignition control unit is expecting. Failure to do that can damage your computer (I hope you haven't already hurt your mo.unit).

    I'd recommend calling Motogadget and asking if the resistance you're seeing in the primary coils will work with your mo.unit.

    -Jon

Bikesmith wrote:Clintinz,
    The fact that you're using the mo.unit is 100% key to what's going on. All the advice everyone has been giving you is based on the assumption that you had stock electronics.

    I have no idea if the mo.unit is compatible with the stock k100 coils. Generally, the key is to use coils with resistance in the primary that matches what your ignition control unit is expecting. Failure to do that can damage your computer (I hope you haven't already hurt your mo.unit).

    I'd recommend calling Motogadget and asking if the resistance you're seeing in the primary coils will work with your mo.unit.

    -Jon

Thanks Bikesmith,
ive seen many many examples of people using these mo.units successfully with k100's, and apparently they are super capable little units. all the readings im getting on my phone (from the mo.unit) are in the expected range, and from my basic understanding the mo.unit isnt inbetween the ingnition unit and the coils. its just replacing the fuse box (which is now my glove box). Is there a way to test the ignition unit is sending the correct signal to the coils?

Bikesmith wrote:
 I've been running Dynatek DC1-1 coils in my K100 for thousands of miles and they work great.

     -Jon

just had a quick look for these in New Zealand. $200 a piece. It would be cheaper for me to buy second hand ones from overseas!

Try a different multimeter. If it isn't the multimeter, then you'll likely need coils.

2V K100 models didn't have a side stand switch in the USA and I doubt models elsewhere had them. The side stand switch was used with the Motronic engine control systems in the 4V models.

Used 2V K100 coils for sale in the USA are uncommon and those obtained from a used Brick are likely to be near death unless they are 2V-model coils with orange-tipped secondary terminals. Used coils seem uncommon is the EU, too. New OEM coils here are nonexistent right now.

Laitch wrote:Try a different multimeter. If it isn't the multimeter, then you'll likely need coils.

Tried a mates multimeter then we stood around scratching our heads and decided it’s best to get replacements… so now the question of which ones? 

I’ve heard in the forum the later model 8v models had better coils? Does anyone have mode numbers? Not the orange top ones are they? They seem to be from 16v K’s

Alternatively I’ve found these and am considering going new. 

https://www.bskspeedworks.co.uk/k-ignition-coil-ht-leads.html

Clintinz wrote:

92KK 84WW Olaf wrote:How did you disable the clutch switch? The clutch switch and the two brake switches are same parts, same connectors in the loom, easy to get the wrong one.

The bike definitely had a side stand switch but I’ve Completely rebuilt the bike and put in mo.unit blue so wiring is new (and a possible cause of issues) but I’ve been testing all the way. Everything except ignition as that was last of all.

I am not aware of any 2v K that has a side stand switch. I have all the Ks in my signature and only my K1100 has the switch, its also on 16v K100 but I dont have any of them. If your K did have one then you dont remove it, you must by pass it as in short it out. Absence of any spark at all can be Hall sensor issue either at the plate or in the wiring routes. If you have a 2v K pressing the start button should run the fuel pump, if you have a 4v K the fuel pump should run when you turn on ignition but the side stand switch needs to be by passed [as opposed to simply being removed] for that to happen.

Considering that a set of Realm Engineering HT leads is around £50 and a set of coils is £mortgage*, that £149 + import duties actually looks like a bit of a steal.

* where mortgage = £60ea for s/h coils and £54ea for EnDuraLast.

Phew! Possibly managed to find some in NZ, just getting the tested. Now to confirm there are. No other problems. I have been testing my leads. Should I be able to get some reading of resistance through the lead? Currently 0 ?? !

Clintinz wrote: Should I be able to get some reading of resistance through the lead? Currently 0 ?? !

If you have OEM leads with a metal cap on the spark plug end, there should be ≈6KΩ resistance in the wire, and you should be using non-resistor spark plugs. If you have non-resistor wires, you should be using resistor spark plugs.

Was troubleshooting a low VM reading issue on my K, and thought to check Primary (and secondary) coil resistance.  Primary was a bit high at 3 ohms, however the secondary resistance was really high!!  One read infinity and the other was at about 56 Megaohms.  Fortunately have spares from a 25K bike I'm rebuilding and they checked in spec with 2.3 Ohms primary and 10K ohms Secondary.  Bide was running flawlessly on the original set, however changed them out anyway.  It was amazing how the bike ran with no known apparent issues.  NO change in ops with the newer coils?!?!

The issue I had was with the voltmeter, was tracing the power wired to the BMU Green Black wire that feeds the "Connection for Special Equipment"  figured I had a BMU that was dragging down that signal so changed it out with the parts Bike BMU unit and it appears to be better.  I have yet to take the bike for a test ride as the voltage starts out fine, but as you ride it varies from 14 down to a bit over 12 volts to 13.5.

Volt meter was changed with a new unit and it matches the removed one, so the indicator is not at fault...  Ground is solid as well....

We'll Let the group know of the test ride results...  Hopefully tomorrow...

I wish one day, I'll know what's the point about replacing a bulletproof reliable electrical equipment by an approximative M-Unit not designed to fit the specific architecture of the Ks electrical system, particularly with people without skills in electricity.
I can't belive that fashion and compulsive consumerism are the only answer. There should be something else to explain that, like an asian philosophy about an initiation by getting rid of everything unnecessary until you reach the stage where you don't even have a running bike but an eternal project. So eternity and projection are now the same, you are mastering the time by chopping undemanding rear frames and confusing previously neat electrical diagrams. And you become a god - or at least a holy man ( if you have any allergy or intolerance, please mention it to our online support for a refund).

In France, we have a world for this: "moutonnisme", that could be translated by "sheepism"
Logical that it's a common behaviour in NZ, after all.

 see above post

All well and good using the later model coils   ofg k1 and k100 16v or k1100

You do relize that the current going to them has increased from 3-4 amps to somewhere near 12 amps....Per coil

 I just wonder when something either upstream  ..read icu under tank ...or downstream .. wiring from  efi relay  will fail

I wouldnt like that at all ....just waiting for inevitable fail

Sorry not going there anytime soon

Might be ok for the cafe racer types....who may have a push home under a killometer

But on a 2500 klm run out in the country  where the nesrest sensible help maybe hours away by taxi ....no good relying on paid roadside assistance...they just dont know...best you could expect is a reasonable overnight stay whilst they flatbed you prize and joy to the nearest depot  who also dont have a frigging clue 


Dont mention you have a k bike at all ...best option is to explain it  as a vw.......

jbt wrote:I wish one day, I'll know what's the point about replacing a bulletproof reliable electrical equipment by an approximative M-Unit not designed to fit the specific architecture of the Ks electrical system, particularly with people without skills in electricity.
I can't belive that fashion and compulsive consumerism are the only answer. There should be something else to explain that, like an asian philosophy about an initiation by getting rid of everything unnecessary until you reach the stage where you don't even have a running bike but an eternal project. So eternity and projection are now the same, you are mastering the time by chopping undemanding rear frames and confusing previously neat electrical diagrams. And you become a god - or at least a holy man ( if you have any allergy or intolerance, please mention it to our online support for a refund).

In France, we have a world for this: "moutonnisme", that could be translated by "sheepism"
Logical that it's a common behaviour in NZ,  after all.

Well said!!

jbt wrote:So eternity and projection are now the same, you are mastering the time by chopping undemanding rear frames and confusing previously neat electrical diagrams.

Sounds useful to me. Tardiness can be a real problem for some people.

Went for a 100 Mile ride yesterday....

1) Absolutely no change in operation, performance and gas mileage with the Parts bikes coils that met resistance specs...  simply amazing that the ones removed had infinite resistance on one and the other had 56 Meg ohms...  My theory is that the coils in the first had an open, but small enough for the gap to be made to fire the plug...  The other with very high resistance the same.

I don't know at what period one should check these in mileage or time to inspect this to prevent a shutdown or very rough running on a long trip.  I'm thinking maybe 2 Years and at every clutch spline lube at 25K Miles?


2) As far as the low voltage thing, the replacement BMU saw a steady 13.9 Volts so the removed BMU was at fault apparently.

I'm thinking of removing the old BMU CB off its base and soldiering BMU bypass wires put the cover back on then go LED on the Tail Brake Lights....

As far as replacement coils has anyone have experience with these?

https://www.euromotoelectrics.com/product-p/edl-coilk.htm

acftfliehr wrote:As far as replacement coils has anyone have experience with these?
https://www.euromotoelectrics.com/product-p/edl-coilk.htm

A customer can trust EME for selling quality products and backing them up if they fail. I had them send me - under warranty whilst travelling - a complete aftermarket Airhead ignition system because they didn't want me to have a second component fail on my trip. They told me to not bother sending back the components I did not end up needing.