About two weeks ago I had a problem with the K100LT.

It started normally when I took it out of the garage for a run. Put gear on and went to restart and it didnt go. Battery was fine, fuel pump was clicking when ignition was on and fuel pump was running and returning fuel to tank when I pressed the starter button. No action from starter motor, not running or trying to engage or anything.

Subsequently I replaced the starter relay/solenoid. While I had this out and was waiting for the new one to arrive I also stripped and cleaned the starter motor but to be honest it looked fine inside.

I put the starter motor back reconnected to the old relay and it started once and problem was same. Couldnt get it to go again.

This morning I put in the new relay, checked everything and it ran fine. It stopped and restarted maybe a dozen times and was fine to the point that I was now sure it was solved. Then on the last one it cut out and wouldnt start again. Nothing from starter motor. This is with the new relay in so I know its not the relay and dont think its the starter motor now. I did think if it was a problem in the fuel injection system that I would get the engine turning over and not starting rather than not turning over at all.

Any advice?

Olaf, as to not cause confusion, I'll delete the other two identical posts.

blakey wrote:Olaf, as to not cause confusion, I'll delete the other two identical posts.

Thanks I was ready to do the same. Good moderation.

Sorry about the three posts, not sure what happened here. Olaf

Would it be a problem with the water temperature sensor?

I don't remember if when overheat is detected, the injectors are cut off or the fuel pump.
Definitively, the bike won't start before it cools down.
As the temperature sensor is a double unit (one for the overheat light on the dash and one to control the EFI), the overheat light may not be ON but the EFI may get a wrong signal.

CF

Maybe have a look at the stater button on the right hand side switchblock? Take the switch apart to see how clean the button is?

Check the battery voltage when starting the bike. It may appear fine, but under a load there may not be enough power to start the bike?

When it starts next time, give the ignition key a wiggle to see if the bike stops.

Thnaks for replies and will see how I can go through these.

Battery was replaced 18 months ago, when it was down it still turned over the engine more slowly but not enough to fire. The battery is turning over fine and in fact just to be sure I took it out and fully charged it.

The temperature sensor I can check, the dash light comes on to show it is working but I have not checked beyond that. If this kicks in does it prevent the starter from engaging or does it prevent the engine from firing? I understood it would just prevent firing.

Starter button I can check, but when I do press that the other functions work. As soons as ignition is on the clicking sound is heard. When I press the starter button the fuel pump can be heard running and you can hear the fuel returning to the petrol tank.

I just read another post about load shedding. If I turn on lights and press starter button they dont dim suggesting the relay is not getting power for the starter. Or that I did not clean the starter motor properly even though it has worked after I did it.

Olaf Maxwell wrote:
The temperature sensor I can check, the dash light comes on to show it is working but I have not checked beyond that. but if this kicks in does it prevent the starter from engaging or does it prevent the engine from firing? I understood it would just prevent firing.

Hummm

If I recall correctly the temperature light should NOT come ON when you turn the ignition on.

Crazy Frog you are correct. I should have said battery light. The temperature warning light does not come on. This problem is happening from cold which leads me to think the temperature switch is not the problem.

92KK K100LT wrote:Crazy Frog you are correct. I should have said battery light. The temperature warning light does not come on. This problem is happening from cold which leads me to think the temperature switch is not the problem.

As I said, the temp sender is a double unit, and the one feeding pin #10 of the FI computer may be bad without affecting the light on the dash. Even when cold, it could send a wrong signal. Check the resistance between pin # 10 of the EFI and the ground. (resistance should be checked at the plug and NOT at the computer pins.
Also, check the EFI plug (over the battery). I saw more than one this plug partially disengaged (when you ride in a pot hole or a big bump) and creating intermittent problems later.

Water temperature sensor resistance:

There are two sensors in the one unit. One is the sensor for the fan and light and the other sends signals to the computer so that cold starting and over temp shutoff work if that side of the sensor is short to earth then the computer thinks the temp is way to high and wont allow the engine to start by cutting the fuel injectors. Also if there is no connection the engine wont start, probably a safety feature to prevent the engine being able to overheat and not have the cutout feature.

Rick, this is very useful. But when you say that the engine wont start, do you mean it may turn over and not start or not turn over at all? Whatever this is, it unfortunately is intermittent so its electrical somewhere.

I will check all the conenctions under the seat, they are easy.

Sorry, I thing I am wrong in my diagnostic.
The starter motor is not turning but the FI is working right?
If you unplug your starter and feed power to the connector(+) directly from the battery, does it turn?
When you press the starter button, do you get power at the coil of the relay(black/yellow wire).
If yes, it maybe a defective relay if not, I would check the starter button itself.
Have you check my diagrams Here?
Select starter and you will have a full detail of the components to be checked.

CF

Crazy Frog, the headlighlight does not dim so I take it starter motor is not drawing the current at all. I put in a new relay so I must now check the relay is actually being activated. Having put in new relay I am inclined to think the signal/power to the relay to activate the starter is not being generated. I will check the connections back to the handlebar switch as it would seem to lie in that direction. However I do know the starter switch is working because it activates the fuel pump when I press it, can hear the return petrol being pumped back into the petrol tank.

Is the clutch switch/neutral detection working? If these indicate to the system that the bike is in gear then the starter motor will not run to prevent the bike lurching forward.
Regards,
K-BIKE

K Bike I will check that one. The wires from the clutch lever were disconnected when I bought the bike but maybe worth checking. It hadn't caused any problem and it doesn't start if in gear but does start in neutral. I never had the habit of starting in gear with the clutch held in so it didnt matter to me and I never reconnected them.

You might have something with that because when it happens its not drawing current to dim the lights so I am suspecting some electrical contact between starter relay and starter button or else an inhibitor/sensor that is preventing the starter relay from receiving the signal to engage the starter.

It seems like you have an open circuit on the starter relay signal.

And as your fuel pump is starting, it confirms that your starter/clutch/neutral
interlock is alive and well, no need to examine that.

Thanks guys, this is helpful in narrowing it down. I am faily sure it is more an annoying than serious thing, just takes time to sort it. I hadnt taken the petrol tank off but seems thats the next task.

Did a bit more checking this morning.

Horn not working.

Flashers not working unless you keep switch depressed.

I have a manual override on the cooling fan [for cold weather riding.......lovely warm air wafts up around you] also not working.

Brake switch fine, fuel pump fine, lights fine, headlamp flasher fine.

All the posts on connections would suggest I have some suspect connectors under the tank so I will look at those and check the load shed relay before going any further.

Thanks too for all the help, keeps the parts bill down.

Olaf

About no function at horn, flasher and fan, check fuse #7.

Since you got headlight + flasher and brakelight, confirms that LSR is functioning
(LSR contacts is closed).

Inge thank you. That seems to narrow it down to some connections under the petrol tank unless the handlebar starter switch is faulty in cutting out just one circuit.

The problem must be somewhere after the switch assy connector, since your fuel pump is starting.

I would guess the starter relay signal connector.

Inge I will check on that one. But something else is up because the indicators dont stay on. However its easy once I get under the petrol tank so will work there at next weekend.

Inge K. wrote:About no function at horn, flasher and fan, check fuse #7.

Since you got headlight + flasher and brakelight, confirms that LSR is functioning
(LSR contacts is closed).

Have you noticed that the horn relay's coil is fed from the temperature unit (green/brown)?

Green/white from the temperature unit goes to fuse #6 then changes color to green/red and goes to the FI relay. At the relay there is a double connection and the second green/red feeds the injectors.

Would the horn not functioning be the result of a bad temperature unit or a bad water temperature sensor or bad FI relay?

This is odd and I have seen bad temperature sensors acting foolishly.

Are your injectors getting power (permanent positive)?

I just had a quick look at the wiring, but the fact that the horn is not working leads me to direction.

I may be totally wrong, but it is first checking and a second opinion is welcome.

Cf

Crazy Frog wrote:Have you noticed that the horn relay's coil is fed from the temperature unit (green/brown)?

Or the other direction, on my diagrams fuse #7 feeds horn relay coils and contacts, terminal 15 at flasher relay and terminal 15 at temp. relay...which is the input for the relay output contact (A2) feeding the fan, and isolated from the rest of the temp. relay.

Posts are being very helpful. Due to work I have not had time to sort this but will tackle it in the morning.

I finally got back at this today, tank was off and good access to everything underneath. There have been a few modifications but since the bike has been fine for the last two years I didnt go at it other than open up and remake the connections. Also when I had the tank off I noticed coolant level was low, took 300ml. I will change coolant in summer.

Now for the bad news, I still have the problem. The bike started and ran perfectly for about a minute at the right tickover speed and then cut out. It would not restart, when I press the starter button the starter did not turn over although the fuel pump could be heard running and the fuel was being returned to the petrol tank.

Does this narrow the problem down?

Olaf

If all other electrics does function as it should, and it`s just a suddenly stop and non functioning starter relay which is the problem.......

I would take a closer look at the connector to the ignition ECU (under the front of the tank), as the starter relay coil is grounded via this one and if this connector have become lose or you have corroded connections (feed, ground) also the ignition would be lost.

Check if you got spark at the plugs before you start,....as it could be intermittent.

Good luck!

Inge that is good and I will look at that again.

I know the starter relay is good because I got a new one.

The thing is that when the bike starts it does so and runs fine. I did wonder was it a case of starting and then suffering fuel starvation but if that were the case the starter would turn over, at the moment it doesnt. I have both a cut out and then no start so its pointing to a combination. I tried to keep it running for as long as possible but something electric is cutting it out, at least I think its electric because it doesnt misfire the way I would expect if it was fuel starvation.

Easy enough to get the fuel tank off so I will do it again.

can i just throw something in the mix ?

starter motor brushes ....

and main earth cable

the starter uses its path to earth to pull in the load share relay when not being powered ....but if the brushes were badly worn ...could this be problematic with the no motor turnover start issue?

i didnt see if the lights were going off then back on ...but i think heavy current draw to the starter could be part of the problem ...especially if a brush had "droped " and now was across 2 comutator sections , i would imagine that current draw would be extrodinary and might be pulling the battery way low on the volts front ...

to prove this ...get some aligator clip leads and multimeter and hook up to the battery do a start process and monitor the volts . if the volts stays high ...it could be the earth cable becoming lossy

alternativly probe the fuses whilst also doing a start and just see how low the voltage is getting durring a start process

compare the results

but i agree with inge on the under tank electronic ignition computer could be needing some attention ,

we have seen modifications on ex official bikes ...and i wonder if some of the cutoff cabling is on fact dropping power to some critical components

I forgot to mention.....starter motor stripped down about two weeks ago, brushes were good but I cleaned everything there.

hope you at least linished the armature ...i would advise looking at a pic of new parts ...brushes might look good but we have seen the springs that apply presure corroding up with little push effort left in them

from memory there is a minimum length needed (8mm)?.for the brushes

just a heads up

I think you will find that it is not the eth behind the starter that is causing the problem because the power to the engine electrics, eg the ignition and FI system do not rely on that earth to work, it is only the load shed relay and starter motor itself that use that earth.
If it is electrical it is the ignition switch, right switch block or the power associated with it.
You may have two seperate problems but the sudden stopping is not from the starter earth for the loadshed relay.

Thanks guys and a lot of useful info:

1 Starter cleaned out, brush springs were good, also it does turn over perfectly when it does work, never sounds tired or slow and starts quickly.

2 I am getting suspicious of the right hand switch gear, there are a lot of posts about it, about kill switch and others. The sudden cut out mystified me because I would expect if it was an interruption to fuel supply that there would be a misfire first and also that the starter would work even if the engine wont fire. A further check to day revealed, horn does not work, indicators/flashers do not stay on unless the switch is held down, front and rear brake/stop light does work, lights work correctly, the fuel low warning light was also glowing in the manner the charge light glows when you use the brakes at night. Tank is almost full, 24 miles done from full tank.

3 I keep thinking if it was an ignition control unit that the starter would at least turn over after the engine cuts out. It doesnt but the fuel pump still works.

92KK K100LT 193214 wrote:3 I keep thinking if it was an ignition control unit that the starter would at least turn over after the engine cuts out.........//////........... It doesnt but the fuel pump still works.

1. That`s why I earlier mentioned ignition ECU connector....if you got a problem with that connector, your ignition would be lost and the starter relay coil won`t be grounded, that`s the reason to I suspect this, since both faults occur at the same moment...as I understand it.

2. Since your fuel pump functions when you push the starter button........your injection relay getting signal, and this confirms that your RH switch assy and its connectors functions as it should.

3. Regarding your horn, indicator, front/rear/stop light problem........this being a bit confusing as it points in opposite directions.
But could be a quite other problem........

4. I would advice that next time you get the problem with engine cut out and non functioning starter, measure signal and ground at the starter relay.

I got at this yesterday and to be doubly sure took out starter again and retested, passed with flying colours.

Starter relay is also good.

Bike started quite a few times and then cuts out after maybe one or two minutes. no starter then.

ICU terminal cleaned and checked, took off connector cleaned all and refitted.

Cleaned inside both handlebar switch assemblies.

Notes:

All fuses are good.

Front and rear brake lights working.

Dash warning lights ok.

Both left and right hand flashers are not operating. However, when I use and hold the button down either the left or right hand flasher all indicators flash at the same time like hazard warning lights and both left and right hand warning lights in clocks light up.

Horn not working at any time, horn checked and good.

Left hand main dip switch works fine.

Right hand lights work fine, kill switch works fine, havent but will check power from starter button on handlebar, must find other end.

Should I suspect ICU????

Olaf

Check the no 7 fuse, test it or even replace that is usually what causes the indicators all flashing when you hold either switch

+1.

Fuse #7 feeds switched power to flasher relay, horn relay and temp. management relay.

I will check that again , last check it was ok but maybe a dodgy connection somewhere near it could do the same thing.

Olaf, is there any other brick rider near you that could allow you to swap out their icu to try. It would confirm or eliminate any suspicions about your own unit and help narrow down the possibilities.
88KE

A jolly good suggestion nand one you might regret since I could take it out and put in my pocket and go meet a willing victim...I do make a trip to Dublin/Kilkenny/Carlow most weeks.....but if its an LT it is a bit of strip out job for someone, copious Chardonnay or Chateauneuf du Pape or similar might help. Afterwards of course.

I am thinking it must be something in there but the indicators coming on like hazard warning suggests something. Its like after starting it looks for a signal from somewhere and which is missing causing a cut out.

If I have an injector problem does an injector problem prevent the engine turning over? Does a temperature sensor problem prevent the start motor turning the engine over? I dont see the kill switch can be doing it. When I looked in the box under the tank I see the BMW immobiliser system is removed, the round plug is still there but nothing connected to it.

I could go a glass of Chateau Neuf after a spin to The Peoples Republic of Cork!! If it gets that far I could take a spin down and you could try my ICU in it.

Have you cleaned the kill switch? I was warned on another Irish forum not to use it to stop the bike as this would lead to trouble. I turn mine off with the key. If the kill switch is working effectively the only thing you should get in either L or R off positions is the dash clock - no other electrics. In the normal postion you should have everything light etc etc. Re injectors etc I'll leave that to more experienced people...I'm not a real mechanic .

88KE

"If the kill switch is working effectively the only thing you should get in either L or R off positions is the dash clock - no other electrics."

Not so. The only thing the kill switch turns off is the engine. With the key turned on and the kill switch left or right all lights and indicators still work.

What could be keeped in mind is, if the kill switch circuit is open....most warning lights would remain dark.

Inge the kill switch does shut down the warning lights but the lights will stay on.

I am thinking that the ICU must be looked at and also any sensors that will cause the engine to shut down. So far temperature sensor seems a possibility. Fuel pump stays running and can still be heard being returned to the petrol tank so I expect its ok unless pressure sensitive. After that I am at a loss.

88KE and 92KK guess that makes me a 86KY , My spare ECU's and a lot of other bits will be in Athlone this weekend if you happen to be up that way. Have you checked the connections on the starter relay when your problem happens? Are you getting the correct readings? I suspect something simple is being overlooked.

I reckon something simple too. Starter relay is new, starter motor cleaned and tested and fine, ICU connections cleaned, funny though the fact that the left and right indicators come on together makes me wonder is there an earthing problem. This goes through load shed relay. Trying to get my head around it. It does start after bike has been sitting, always starts the first time I try it. then cuts out after a few minutes.

Byt he way 86KY and 88KE we should try and get some more on board too, I know a few more Ks in Cork. Olaf

92KK K100LT 193214 wrote:I reckon something simple too. Starter relay is new, starter motor cleaned and tested and fine, ICU connections cleaned, funny though the fact that the left and right indicators come on together

And if your horn still doesn`t function, check post 37 & 38 one more time.

I think you got two different issues, and your flasher/horn si not related
to the cut out/non start.

I really appreciate the help on this.

I went at it yesterday and today.

Took out ICU, cleaned everything up, it did look fine and no evidence of any water ingress inside it, like new. Refitted and connected back up. No difference.

Swapped some relays around in the electrical box under the tank. There are three identical ones numbered 311. The book says 2 but I think the third is the headlight relay. No difference.

Disconnected and reconnected and clealed the multi connectors from the handlebar switches. No difference.

Swapped fuse 7 with a spare fuse and no difference.

When I put all back together it ran for about 10 minutes no problem. Used kill switch quite a few times and it restarted normally, no problem. At about 20 minutes it cut out and problem showed up again. I tried keeping revs up to see if this would prevent cutting out, it did not help. Actually seemed like fuel cut off. But when I press starter button again the fuel pump is working fine even though the starter fails to do anything.

This time I kept my finger on the starter button and after about 15 seconds the starter engaged and turned over briefly. This happened a number of times...delay and then engaged.

So, my guess is the starter button [checked connections], load shed relay [not checked], starter relay [already replaced with a new one] or starter [twice taken out and stripped -but I am open to being told I have not done it right]. As for the temperature sensor I know the coolant level is correct. Its due a change on next service in about 2 weeks so am leaving alone.

If I turn on the lights and then press the starter button the lights do not dim so there is no power drain happening making me wonder is it handlebar switching. Would running a wire from battery to the starter motor when this happens, as a test, be risky?

If a guess is the ICU I can get one from motorworks, same with load shed relay.

Questions now is: could there be a fuel supply/fuel pressure/injector problem that could cause this? If there is insufficient fuel pressure or fuel supply [eg fuel filter/pump fault- tank has done 23 miles from a full tank so plenty in tank] does this translate into preventing the starter from engaging? Reading posts re injectors I am wondering could this be a problem?

Was anice sunny day for a run and a little frustrating.