All up and running again. All I need to do now is tidy up the sidecar wiring and give it an oil & filter change and its ready for a rego inspection.

Here's what I found;

The intermittent starting and stopping problem was an earth lead that had been left off the battery by the PO. It would earth out on the frame from time to time and the bike would go until it was moved.  It wasnt easy to spot as it was hidden under a sidecar mount. Connect this to the battery and it would start and run well FOR A WHILE, then it would stop, but would restart when it had cooled down. Classic HE sensor failure. Luckily I had a new sensor on order from Motobins and even better it showed up today. Fitted it and all is well in the universe.

So now I have 2 u/s HE sensor plates. I'll put new sensors on these and put them away as spares.

Many thanks to all who contributed to the fault finding.

Good one

Now ride

Great to hear Phil . Good luck with the rest of it

Registered, but not back on the road. The battery shat itself and wont hold charge. This happened during the blue slip inspection of course. I'll chase up a new battery tomorrow.

More problems - or the same one back again.

What it does is start and then immediately stop again after maybe 1 or 2 seconds. It was running well up until last week. I did put a new battery in.

I did get it to run for a few minutes once, then it started missing and eventually stopped. It almost sounds like its running out of fuel but there is enough in the tank and I can see the returned fuel from the pump going back into the tank as it is cutting out.

It has a new pressure regulator, fitted by the po, and I checked all the fuses and relays. All seems normal there.

I'm wondering if I have a sensor somewhere which is playing up and the Motronic unit is cutting off the injectors and/or ignition because it doesnt have that signal. Unfortunately I dont know enough about the system to work out which sensor, or if it is something else.

Any suggestions?

Once it cuts out check to see if the plugs are wet or dry and check for spark at the plugs.
Regards Martin.

MartinW wrote:Once it cuts out check to see if the plugs are wet or dry and check for spark at the plugs.
Regards Martin.

Hi Martin,

I pulled the front plug after it cut out. It was dry. It was a bit difficult to check spark after it cut out because pressing the starter just starts the whole cycle over again. What I did was leave the front plug out and try a start on 3 cylinders. It sort of did and I did notice that I still had spark as it ran down the revs after it had cut out.

I take it from this that its the injectors that are being switched off after the initial start and I still have fuel being supplied to the fuel rail, and spark at the plugs.

So what do you recon?

At least you have a starting point, test the Motronic or go to the troubling shooting sequence post and work your way through it.
Regards Martin.

The Motronic has a rudimentary diagnostic function that you can access with an LED connected to the black diagnostic plug that is somewhere under the seat.

https://www.kforum-tech.com/electrical/PDF/Motronic%20Fault%20Codes.pdf

Point-Seven-five wrote:The Motronic has a rudimentary diagnostic function that you can access with an LED connected to the black diagnostic plug that is somewhere under the seat.

https://www.kforum-tech.com/electrical/PDF/Motronic%20Fault%20Codes.pdf

Interesting - I ran the diagnostics as per the link above and got code 4444, which as I read it says there are no faults stored.

This sort of eliminates the oxygen sensor, TPS, HES, air temp sensor and water temp sensors.

What is left??? Is there a link that connects once the engine is running through a relay or something? Dunno.

There is a connection from ECU to the Motronic relay, the ECU extends an earth to the relay when the start button is pushed and when the engine is running if there is a signal from the hall sensors. If that earth is removed when you release the start button the engine will run for 1.5 seconds same as when the fuel pump cuts out 1.5 seconds after the start button is released if the engine is not going.

Can the injectors be heard ticking with the help of a screwdriver?

What is the tach reading when the engine is running.  The Motronic needs a 700 rpm signal from the hall sensors to keep the fuel pump running.

RicK G wrote:There is a connection from ECU to the Motronic relay, the ECU extends an earth to the relay when the start button is pushed and when the engine is running if there is a signal from the hall sensors. If that earth is removed when you release the start button the engine will run for 1.5 seconds same as when the fuel pump cuts out 1.5 seconds after the start button is released if the engine is not going.

This is sounding hopeful. The symptoms I'm getting sound exactly like this. Tomorrow I'll go searching for an earth starting at the Motronic relay and working towards the Motronics unit. Since it has run properly time to time I'm guessing a bad or loose connection somewhere. The Brown/Blue maybe? from

Well its going again. I'm not saying problem solved at this stage until it shows that it will keep going.

What I did was disconnect and reconnect all the plugs inside the relay box under the tank. I also changed a couple of fuses that looked a bit ropey. The fuses checked out as ok using a multimeter, but the fusable bits looked a bit "odd" and the connecting spades a bit corroded.

The upshot is that I'm not sure which connection was the problem, but its fixed for now.

Its going to fight me all the way, but I'll persist. Yesterday morning I tried to start it and it coughed and farted on 2 or 3 and occasionally 4 cylinders for a while (several minutes) before eventually settling down and running more or less normally, but not as smoothly as it should perhaps.

I pulled the plugs. All were very black and sooty, so I cleaned them and stuck them back in again. Now it ran quite smoothly, so I went to the local bike shop and got a new set. These were NGK's and dont have the nuts on the top, so I couldnt fit them.

This morning I tried starting it and again the coughing and farting went on so I chased up a set of nuts and fitted the new plugs. It now starts quickly and runs smoothly again. A start tomorrow will tell me if that was the plugs or not.

Incidentally its got 91 fuel in it because it was handy at the time (mower fuel). This probably doesnt help it run properly. If I can get it to run long enough to get to a servo I'll fill it with 95 or 98.

Just to make sure, you have the right leads and plugs?
Leads without R and plugs with R.

What plug number do you have now?  The four valve K bikes use NGK DR7EA plugs which come with the nut molded on the plug.

You should be able to scrounge/buy the spark plug nuts from your local mower shop. Most seem to have a jar of them.
Regards Martin.

MartinW wrote:You should be able to scrounge/buy the spark plug nuts from your local mower shop. Most seem to have a jar of them.
Regards Martin.

Here in the U.S. NGK DR7EA plugs come with the terminals permanently attached.  That he doesn't have them on his plugs makes me think he has D7EA plugs which are not the right ones for his bike.

About 15 years ago on advice from an ex BM tech I very briefly tried NGK resistor plugs. They didn't come with nuts. I think Bruce had a set of NGK resistor plugs mistakenly supplied for his K75 also without built in nuts I'll contact him for confirmation.
Regards Martin.

It's possible that there could be DR7EA plugs with built in nuts. I'm also thinking that 20+ years ago you got the removable nuts with the D7EA's.
Regards Martin.

Plugs are NGK DR8EA I think. I've found some nuts, installed them and all runs well. I'll take it for a run this afternoon.

There was some discussion here some years ago but I can't find it as usual. Both D7EA and DR7EA are made with built in terminal nuts and without.
I seem to recall that NGK was the source but cant remember anything other than that.
I tried DR8EA in my K11 because I could not get the 7s and very quickly went back to the DR7EA as soon as I could get them. Cold starts were the biggest problem but they sure didn't get along with the K11.

DR8EA plugs are a heat range colder.  For short haul riding in cold weather they may have fouling issues.

Martin, how old are the plugs in your photo.  The 2019 U.S. catalog image of the DR7EA shows the nut and I've been getting them with the nut since about 2016.  Maybe there is a different spec in OZ.

Here is the catalog page with images of the two plugs.  The D7EA is image 296, and the DR7EA is image 312.

https://online.flippingbook.com/view/17923346/34/

Gryph downloaded straight off eBay Au. I also had a look at eBay US and you can get both types in the US, no nuts does seems rarer. I've never encountered either the D7EA or DR7EA with built in nuts. However on eBay AU both types are shown. When I first started buying D7EA's I'm pretty sure that they came with the nuts loose in the box.
Regards Martin.

Gotta love the mixture of Imperial and Metric measurements...

MartinW: same here. I have a bag of spare brass nuts now, just in case.

I got a couple dozen nuts by calling NGK tech support.  They sent them, no charge.  I use them on my 2 valve bikes.

NGK Australia will send nuts at a price and also charge a hefty postage charge.
Regards Martin.

I guess they want you to use Bosch.

Unfortunately I can't find Bosch with removable nuts. I'm running 5ohm NGK caps which any day now according to a BMW guru will blow my computer, and send me to hell.
Regards Martin.

So getting back on topic, yesterday I took it for a short 15km run out to a mates place. On the trip out it started easily and ran well. All good. On the return journey it was hard to start and missed and went on for maybe 30 seconds then settled down and ran normally. This morning it started easily and ran well. The only thing I can add is that the last km into his place is slow 1st gear stuff because the road is crap. Maybe the slow running fouled the plugs. I'm thinking I should either get a set of the DR7EA NGK's or the original Bosch.

Rockman wrote: The only thing I can add is that the last km into his place is slow 1st gear stuff because the road is crap. Maybe the slow running fouled the plugs. I'm thinking I should either get a set of the DR7EA NGK's or the original Bosch.

The proper heat range is a good idea.  15km is the bare minimum to get the engine up to proper operating temperature.  I would take it out for another ride today at normal highway speeds.  About 40-50km, then pull the plugs to see what they look like.

A few things;
Yesterday I checked all the coil and plug connections including the HT leads. One was not seated properly (not going over the spark plug). I fixed this. I also pulled the plugs. All were black and sooty, but not wet. These are the DR8EA's. The 7's havent shown up yet.

After this it sort of starts but is a little "cranky", but an improvement. It had a slight miss when revved.

While I was fiddling about in this area I noticed that the "choke" cable at the throttle body end was not seated properly. I reseated it but noticed that there was a lot of freeplay. Regardless, it goes to a fast idle on the first click and a faster idle when all the way around so I've left it alone for now. The slight miss when revving seems to be gone.

I wont know if all this has done any good until tomorrow when I try to start it again from cold.

Once running it goes well, but I havent had time to take it for a good run. The plan is to fit the DR7EA plugs and then take it for a good run somewhere and then have a look at the plug colours. The bike sat for well over 12 months before I got it so probably needs it.

As an aside - the ABS lights flash all the time. I tried doing a reset a number of times and gave up in the end. I pulled the ABS relay and now only have one light flashing. Whats the easiest way to stop this? Take the bulb out or disconnect the ABS unit completely?

Disconnect the ABS unit I recall Tosi saying it is a good idea to pull the ABS plug but I cant remember why.

There is a glimmer of hope - today it started like it should and ran like it should, but we've been here before. Time will tell.

Today I did about 100 km without any problems. Looking hopeful.

When the 2 ABS lights flash, do they flash together or alternately?

92KK 84WW Olaf wrote:When the 2 ABS lights flash, do they flash together or alternately?

 alternately. What does that mean?


As for running, this morning it'd start but not keep on running. I remembered that yesterday I fiddled with the wires around the injectors, in particular the one that runs forward from the fuel rail, so I gave it a bit of a tug and all was well again.

Looking at the wiring diagrams it seems this goes to the oxygen sensor - can someone confirm this?
In any case I'll chase it along and re-make any connections.

Forward from the fuel rail = water temperature sensor. I've seen a few with green corrosion on the pins, so giving it a tug could just be temporarily breaking through the crud. Or remaking a broken connection. The bad news is you need to remove the airbox to get at it.

Dai wrote:Forward from the fuel rail = water temperature sensor. I've seen a few with green corrosion on the pins, so giving it a tug could just be temporarily breaking through the crud. Or remaking a broken connection. The bad news is you need to remove the airbox to get at it.

Sounds like a job for next weekend. Today I did about 84 miles (~134 km) no problem at all, but as you say the "tug" fix is probably temporary and it needs to be fixed properly.

You can get at it without removing the airbox but it's a bit awkward. Also - at the risk of teaching granny to suck eggs - if you're going to pull it out to take a good look, don't forget to drain the coolant.

Dai wrote:You can get at it without removing the airbox but it's a bit awkward. Also - at the risk of teaching granny to suck eggs - if you're going to pull it out to take a good look, don't forget to drain the coolant.

Radiator off job to do that?

Nah - I have a love affair with Duck's method of draining the coolant; stick a bowl under the engine and pull the hose off the water pump. It really depends on the angle that the temp sensor has come to rest after being tightened down. If you're lucky, with the air of a small bright torch you might be able to see all sides of the pins. If it does need to come out for cleaning; well, see above. There is enough room to get a spanner in if you're patient.

I'll let you know which method I use once I've had a chance to peer into its deepest darkest recesses. I am hopeful I dont have to do much more than clean up the connections.

I only ever drain it by removing the bottom hose as you suggest.

But my fingers really struggled on getting at the sensor from behind the radiator. I was able to get the connector off but that was it. 

Rear seal on my K1100 shat itself on Thursday so its getting the works....a new clutch etc etc etc. Good prices at Tills.de for all the new parts.

Rockman wrote:

92KK 84WW Olaf wrote:When the 2 ABS lights flash, do they flash together or alternately?

 alternately. What does that mean?

When you start the K1100 the ABS should lights flash simultaneously. The ABS runs a test and the first part is at ignition on. If they flash alternately at that point there is a fault. The ABS is voltage sensitive and if the battery is off peak voltage they will flash alternately as soon as you turn on the ignition. They may flash together and change to alternately as you hit the starter, again less then full voltage on the battery. They will also do that if one of the wheel sensors is out of clearance spec. If they flash together as soon as you get rolling they should go out and you have ABS active. If they change to alternate flashing then you have a fault in the system.

Pay close attention of the wheel sensor clearances. Over time I have had 2 final drive big bearings fail. On the K1100 the final drive failure was sudden. What I discovered is that the bearing can develop imperceptible play, but enough to upset the rear wheel sensor alignment and trigger an ABS fault. The sensor and the ABS ring are on different sides of the bearing so any imperceble play in the besaring changes the clearance. After a bearing replacement my ABS problems went away

92KK 84WW Olaf wrote:

Rockman wrote:

92KK 84WW Olaf wrote:When the 2 ABS lights flash, do they flash together or alternately?

 alternately. What does that mean?

When you start the K1100 the ABS should lights flash simultaneously. The ABS runs a test and the first part is at ignition on. If they flash alternately at that point there is a fault. The ABS is voltage sensitive and if the battery is off peak voltage they will flash alternately as soon as you turn on the ignition. They may flash together and change to alternately as you hit the starter, again less then full voltage on the battery. They will also do that if one of the wheel sensors is out of clearance spec. If they flash together as soon as you get rolling they should go out and you have ABS active. If they change to alternate flashing then you have a fault in the system.

Pay close attention of the wheel sensor clearances. Over time I have had 2 final drive big bearings fail. On the K1100 the final drive failure was sudden. What I discovered is that the bearing can develop imperceptible play, but enough to upset the rear wheel sensor alignment and trigger an ABS fault. The sensor and the ABS ring are on different sides of the bearing so any imperceble play in the besaring changes the clearance. After a bearing replacement my ABS problems went away

Thanks Olaf. They start off alternating and stay that way. I'll check both wheel sensor clearances.  Since it has a leading link it is very possible the front one is out of spec as its mounted on a dodgy looking bracket. Battery is new so should be ok

I had 5 minutes to spare today so I had a quick look at the temperature sensor location. From what I can see the sensor wiring goes through this plug. Since the section after to plug going to the sensor is pretty well tethered I'm guessing it is the plug itself that is likely to be my problem.




While looking I also found this bundle hidden up inside. Something is bound up in yellow and red rubberised tape. I'm picking its the fuel pressure regulator and it should be attached via the bracket in the middle of the pic - missing screws by the look of it. Looks like I'll have to dig in deeper to fix this properly.  Good news is that it still runs although was a little finicky this morning until I gave the wiring a shake. 95 miles yesterday and a fuel consumption of 14.45 km/l.

Ooo - messy!