I tore down my '85 K100RS a few months back for a complete going over. The parts are back from the painter now and I'm reassembling. Now that the fuel tank is back on, I've tried to restart it, without success. It turns over well, but no fire. I had the bike down to the bare frame, and had to reinstall the wiring loom and everything attached to it. I also took apart the bottom end of the motor and repaired the 6 rivet output shaft issue. I did not disturb the engine timing. I am wondering about the coils and firing order. I assume #1 cylinder is at the front. I'm not sure if I have the spark plug leads and coils set up correctly. Facing the coils on the left side of the bike, the coil on the left says 'Zyl 1 u. 4, schwartz/blau', and the one on the right says 'Zyl 2 u. 3, schwartz/rot'. I have the brown wire in the center position on both coils, the yellow/grn wire to the back (engine side) on both coils, the blue wire on the left coil and the red wire on the right coil. On the left coil, the #1 spark plug lead is to the outside, #4 to the inside. On the right coil #3 is to the outside, #2 to the inside. Does this seem right?

I have confirmed I have spark, and there is fuel pressure at the fuel rail. The plugs appear damp, but not soaked.

It ran before I took it apart. I did disturb the HES but believe it's in the right position.

Please, somebody throw me a bone. (That's Canadian for 'help')

I can't offer advice on the correct firing order at the moment but what I can suggest is to eliminate what we know from the whole equation and the fact you are getting spark indicates the low voltage wiring on the coils is correct.

The HES has an alignment notch which is where I set mine so if it is lined up with that it has to be pretty close. HES also has to be working to create a spark.

I would think if the bike is cranking over and not firing I would expect the plugs to be quite wet.

You have probably done it but worth re-checking all the electrical connections just to make sure they are all firmly seated.

Just checked the Haynes Manual and No1 cylinder is as suspected the front and ignition leads 1 and 2 are the outside connections on the coil and firing order is 1-3-4-2

You have the coils around the right way but no 2 and 3 Ignition leads are (according to Haynes) wrong way round.

Thanks for that Phil. If two of the leads are correct, you'd expect some attempt at firing on those two anyhow. I'm suspicious that maybe the injectors are not getting power, since the plugs are not very wet at all. Is there an easy way to find out short of pulling the rail and injectors and turning it over (messy)?

Put a bulb say 5 watts on the supply line to the injectors, that positive supply is powered all the time the system is in the run or start condition. If the bulb lights you have enough power to drive a bit of current. Then swap tests and put a 12 volt led across one of the injectors they all squirt simultaneously and the LED should be flashing when the bike is turning over in the starting position.
Regards,
K-BIKE

I think you have the low tension coil wires incorrect. When I replaced my '85 motor recently I drew myself a diagram of the coil wiring, ( as suggested by the haynes manual). The brown wires were on the rear of the coils, ie closest to the engine, the blue/black wire was on the front coil, on the middle terminal, the red/black was on the rearmost coil, again in the centre and the two green/yellow wires were on the front, ie closest you, terninals.. As far as the HT leads are concerned, as long as the front coil goes to 1 & 4 and the rear coil goes to 2 & 3, it does not matter in which order as no1 and no4 spark at the same time, its just only one of the cylinders is at the firing point, the other spark is just wasted. I hope this is of some use.

Hi, If you email me at dennis.brown@exemail.com.au I can send you some close up pics of the coil LT wires in correct positions on the bike.

Cheers, Dennis

Dennis wrote:Hi, If you email me at dennis.brown@exemail.com.au I can send you some close up pics of the coil LT wires in correct positions on the bike.

Cheers, Dennis

Dennis, can you post them on the forum?

Thanks

Bert

UPDATE: Robin, I compared your description with the Haynes manual, seems to be some discrepancy. I tried it your way, no change, put them back the way I had them before.

Checked the power at the #4 injector connection, it lights up on both sides of the plug when the start button is pressed, goes out when I stop pressing the start button.

Pulled the plugs (new) they seemed dry. Spun it over without the plugs in, no fuel spurted out. I did my own manual injection into each cylinder (turkey baster) reinstalled the plugs and spun it over, and got a satisfying pop several times from the motor. So it now definately seems fuel related.

I have fuel pressure at the rail, and can hear the fuel pump cycling when turning over. Kinda seems the injectors are not injecting. What to check?

When facing the left side of the fuel tank, left fuel outlet goes to the rail, right outlet goes to the regulator, correct?

When I fitted the new motor to mine, it initially only started on two cylinders. I went thru similar things things to get it running on four. In frustration while it was running on 2 I tapped the fuel rail with the side of a spanner and all of a sudden it burst into life on 4, and has done ever since. The motor had been siting for some years before I fitted it and can only put it down to the injectors being stuck closed. I am not suggesting that that is your problem, but it a possibility>

robinm wrote:When I fitted the new motor to mine, it initially only started on two cylinders. I went thru similar things things to get it running on four. In frustration while it was running on 2 I tapped the fuel rail with the side of a spanner and all of a sudden it burst into life on 4, and has done ever since. The motor had been siting for some years before I fitted it and can only put it down to the injectors being stuck closed. I am not suggesting that that is your problem, but it a possibility>

Mine's been down for about 5 months, took everything off down to the block (didn't pull the guts out of the block) to clean it off (previously painted gold), and then reassembled from the ground up. I'll try tapping the rail...

club_c wrote:When facing the left side of the fuel tank, left fuel
outlet goes to the rail, right outlet goes to the regulator,
correct?

I drew myself a little pic of mine when I took it to bits with length of
fuel pipes etc. My diagram is exactly the opposite way round to your
description. However my model is at least one, if not two, revisions of the fuel tank design later than yours so...

Oops, you are correct wedge. Typing while my wife was talking, too distracted. Left outlet goes to regulator, right to rail on my current configuration.

I've examined all the wiring, and all I can find that is not yet identified is a two wire round multiplug with grn/red and black wires. It comes off the loom with the injector wiring and throttle plate sensor triple plug. Grn/red could be part of the injector wiring, but this one has me stumped. It hangs just behind the intake plenum on the left side of the engine. The engine spins over fine, has spark, has fuel pressure at the rail, but the plugs are dry so something is not communicating with the injectors to tell them to open up.

UPDATE: that looks like it will be the altitude corrector plug now that I've looked at the schematic in the download section. Would my Canadian bike have that? Says US models in the schematic, but may really mean North American... Where would that be found?

I have a feeling the plug is more of a "jumper" i.e. connected or not such that in high altitude areas (they don't have mountains in Europe??) it is connected or vice versa to allow the FI unit to compensate.

Sounds like everything is ok but is it possible the injectors are clogged. Sounds absurd but it appears that was what happened with Robin's bike and possibly others.

You think all 4 would clog at the same time, especially since they all worked before I took it all apart? Looks like maybe I'll have to pull the rail and injectors together, confirm no fuel spray unless someone has a more brilliant, less messy idea... thanks Phil.

That's the tricky thing as the injectors are not timed, they all fire at once as there is only one signal wire and an earth so on that basis it it possible.

club_c wrote: UPDATE: that looks like it will be the altitude corrector plug now that I've looked at the schematic in the download section. Would my Canadian bike have that? Says US models in the schematic, but may really mean North American... Where would that be found?

Post the last 7 digits of the VIN and we will be able to tell you if it's an EU or US bike.

...0041085. Updated my profile with that as well.

Here is what you want to know:
09/1984 K55 K100RS USA.
I believe that this bike was fitted with the altitude plug (green/red and black wires). The vacuum switch which was removed in 1985 has a plug with 2 wires (Violet/green and black).

Ok, so where would I find the altitude plug on the engine? Do you think that disconnect would cause my no start?

I don't have any experience with this device, but I think it was only a jumper.

By the way, thank you for contacting the French people stranded in Pemberton.
They already sent me an Email and really appreciate your offer for help. Vincent has some experience with the K100 and he told me (by Email) that he's willing to have a look at your bike if you connect.

Nice payback. Hopefully it's a non issue soon anyways.

Hi there, mine has the altitude plug conection. I use a simple wire jumper wen riding over 1500 mts and the bike runs better, so I dont think that causes your problem.
I understand that you have fuel pressure, but do you have flow? It Hapens to me that I had pressure but not enough flow due to a cloged filter wich stayed dry for a few months during the engine rebuild.
Best regards
JAP

Now there's a good point I hadn't considered, and yes the tank was empty (nearly) for seveal months. I'm going to check the flow from the pump next I think. I start back to work after 3 weeks off beginning tomorrow, so may not get a kick at this again until mid next week. However, all you K-ers, please keep the thoughts and ideas coming!

UPDATE: good fuel flow and pressure to the fuel rail. I pulled off the rail with the injectors attached and cranked it over: no fuel from the injectors. So therein lies the problem. Injectors are not getting a signal to inject. Next step...? Remember I had the wiring harness off as part of the full teardown. As an aside, the choke light doesn't light up. I haven't checked the bulb yet, but wondering if it could be related to the injector issue.

Coincidences are unusual and it appears you have 12 V going to the injectors but no switching to earth by the FI unit which should be pin 12.

Pin 9 should have 12V which comes from the FI relay which is energized when you press the start button and explains why your light worked on the injectors.

UPDATE: I've conducted the EFI/FI troubleshooting and obviously have a problem. Just dont know what it is. The following is the PIN #, expected value, and my value:

1 10-20 mV 20mV when starter not turning, 70 mV when turning
2 12V .01V
3 12V .01V
4 12V 8V
5 0 ohms 2 ohms
9 12V 10.7V
10 2.5Kohms 1.9kohms @20*C
12 ground to injectors: within limits
13 0ohms 45 ohms

I got nuthin', no ideas. Did I make a major error in reassembling the wiring loom?

No 2 and 3 goes to the throttle position switch but in theory can be disconnected and still work.
13 is connected to 5 which is connected to the airflowmeter and should be at ground which might explain the low voltage on pin 9.

So could just be a bad connection rather than a major error but might be worth checking the connection to the airflow meter especially as it is so easy to get to NOT!

airflow meter, ok, I'll check that in the morn. thanks

Just as a bit of additional information, Pin 9 connects to the airflow meter and also connects to the positive feed to the injectors and one side of the TPS.

So essentially you should have 12v coming off the Fuel injection relay which feeds one side of the TPS, the injectors, Pin 9 of the FI control unit and possibly pin 4 of the Airflow meter.

Pin 13 should also be a direct connection to ground so perhaps follow the wiring back from the FI controller plug to make sure all earths are connected where they should be.

Sorry if I am sending you around in ever decreasing circles as these faults can be but I think the fix is not far away.

Additional info:
Somebody pointed to me that if you are checking the airflow meter at the injection computer plug, it must be done with the fuel tank electrics unplugged. Otherwise pin 9 is earthed via the fuel pump and all the readings between pins 5-7-8-9 are wrong. The airflow meter can be tested by applying 12v between pins 5 and 8 and measuring the voltage across pin 5 and 7 while moving the vane. The reading moves smoothly between about 2v and 12v.

Ok, I've 'checked' the airflow meter, that being pulled it out and confirmed the connection was good, then deoxit-ed it and reinstalled. No change. Is there another possible connection at the other end for it?

Not sure how to apply 12V between 5 and 8 pins.

I'm feeling a bit over my head all of a sudden, still breathing through a straw, but would dearly love to get my head above water.

Wondering about how to test the EFI relay?

Trying to stay 'balanced' here, but frustration is knocking at the door.

If the pump is running, the EFI relay is working.
You can test if the injectors are fed on + 12volts.
- Set up your multimeter for 12 volt DC
- Unplug the electrical connector of one injector.
- put the positive wire of your multimeter to the connection fed by the Green/red wire.
- touch the engine with the other wire of your multimeter (need to be a good ground)
- Turn ON the ignition.
You should read 12v.
Please report your finding and we'll go for there.

Bert

Done. With ignition on: .01V. When cranking, 10.9V

10.9v is not the best, but it should be enough to power the injectors.

Can you do this test again measuring the power at one fuel injector plug? (getting the power between both pins of the plug?

Please report and we will again go from there.
As we have 5 hours time difference, if you post before 16:00 your time, I will still be up a reply.

Bert

roger, going now. I'll take the laptop into the garage with me.

So Bert, you're saying using the same plug, put + on the red/grn and - on the other side?

Yes please and try starting the bike

Done. 0.12v. That doesnt seem good

club_c wrote:Done. 0.12v. That doesnt seem good

Check your personal Email

Bert,

I sent you a MP.

Clubbie

UPDATE: Bert and I have concluded via Skype that all my values appear to be within range when compared to the EFI test chart. As was the air flow meter. Hmmm, so he's sending me an EFI computer for testing.

Now on the off chance all the injectors got clogged at exactly the same time, is there a way to check for that??

Thanks Bert!

Is there a way to check injector function directly? I pulled off a couple of them and put 12v to them (+grn/red, - to the other), but don't think anything was happening. Any way to confirm they operate (open/close)?

Hi there, for the injectors the best is to take them to an specialist (our injectors are the the same used on cars), the cleaning machine has also all the testing facilities and they also change the microfilter.
Best regards
JAP

I went through the starter today to confirm the brushes were clean and bright, hoping that may solve my gremlin, no luck, no change, still have positive voltage on the pulsing ground side. Noted an extra tab on the back of the alternator in the center, any ideas on that? The wiring diagram only shows 2 wires connected to it, and they are already in place.

Gonna have to double check every single connection and confirm the wire colors at each one. Still waiting on Canada Post to deliver the computer that Bert sent out.

The computer arrived today in the mail, but I don't want to hook it up quite yet, want to do some more evaluating.

I went over every single connection today and compared my wiring with the diagram, thinking I'd hooked up something wrong when I reassembled, yet it is all correct, so I can rule that out I think.

Still no power at Pin 2 or 3. With the EFI computer unplugged, on the injector plugs, power on the red/grn, AND the yel/grn when cranking. However, if all the injector plugs are pulled off the injectors, there is no power on the yel/grn side when cranking.

Still want to test the injectors with an LED light, but social functions and work are sucking up K bike diagnostic time.

Any other ideas?

club_c

I feel your pain buddy, I am likewise following your thread and perhaps the problems we are having are related in some way.

some but not all of the symptoms are shared. I'll read your thread carefully when school and time permits and perhaps I can glean something from all the info.

feel free to do likewise.

good luck,
b

PS - hook up that computer! lets see if that works!

Yes, I will eventually hook up the computer. However it is a 'loaner' from this site's administrator, and I want to ensure I'm not sending 240v into it or anything else that would melt it down and cause the site administrator to fly to my house and set it on fire.

hmm.. yes. I believe the technical term for that would be... "bad".