Hello Guys,

I need another help...help....help!!

My bike could start and run reasonably well, I rode on it for about 0.5 hour in town last Wed. On Thursday morning, I tried to start it, it wouldn't start; dash board lights were all ON. I left it. Friday morning I tried to start again, still couldn't start, even though I jumper leaded the battery. This morning again I tried to start it, still couldn't get it run, including using additional strong battery. The starter motor only ran weakly and intermittently.

SO I GAVE UP......

Then I thought the starter motor need cleaning up (?). I cleaned the main ground connection, then the electrical connection to the coil and the 2 censors(?) lower part of the front side of engine.

Brilliant....????? I turned on the key.....holla????

The whole bike is "DEAD", no dash board lights are ON....What's on earth is happening?

PLEASE HELP...I NEED SOMEBODY'S HELP .

THANKING YOU IN ADVANCE....Hope I am a bit...lucky here.

What a week end home work

Additional information:

Only the clock is on, but when I switch the key ON, the clock goes OFF.

I checked the fuses, No. 3,4 and 5 have + current/ voltage; fuses No. 1, 2, 6 and 7 have NO current / voltage. When I switch the key ON, all fuses has NO current / voltage

I check the "Interactive diagram", can it be caused by the faulty Load Shedding Relay?

ADVICE AND COMMENT PLEASE.

Thanks a lot.

I would agree with you that the problem is on the load shed relay circuit.
As the ground of the load shed relay coil is fed by the starter, I guess your starter has to be open and cleaned. You can try to put your bike in 5th gear and turn the back wheel with your hand (back and forth). This may re-establish the contact on your starter.
Removing the starter is a simple operation (only 2 screws). Open it and clean it.
Read this post and you will see that when the starter brushes are worn (or dirty), the electrical is acting crazy.

Bert

If when you turn the key on the clock goes out that points to a flat battery or a high resistance in the circuit between the battery terminals and the main supply/earth.
Regards,
K-BIKE

@Bert,

thanks for the advice. I shall buy a new relay to replace the Load Shedding Relay. Hope this will bring "LIFE" to the dash board, at least. I did remove the starter motor (BMW with Nippon Denso made in Japan), but I put it back before I clean it. I shall take your advice to clean it.

@K-BIKE,
I was thinking the same way regarding a flat battery. But it was still the same when I hooked up jumper lead to a strong car battery

I can't think of logical reason of this yet.

Cheers.

Hello Guys,

I did put a new Load Shed Relay...then turned the key switch ON. I could hear a "click" from the relay and the dash board light was "on" very low light. Right away I turned the key OFF. I thought this might be a flat battery. I was...happy for a few minutes.

I took out a jumper cable and hooked them up, a battery (of a running car) to the battery of the bike...but now there was NO "click", NO dash board light ON.

Still with jumper leads attached and the car runs, I checked the voltage of the battery: 15V. Then I turned ON the key, checked the voltage at the battery terminal: 4V ....very strange.

I took off the jumper cables, checked the battery at the terminals: 12 V. Again when I turned ON the key, the voltage dropped to 4V...

Well, now I think there a possibility of a short circuit..but what and where?

Any advice or comment???? Much appreciated.

Regards.

It seems that an unprotected device (no fuse) is sucking the power.
First, disconnect your battery and plug your booster cables and the car battery. Your bike's battery may have an internal short.
If the problem is not the battery, check and clean the main ground connection on the gear box.
Remove each fuses one by one and check your voltage drop at the battery. This may help you finding the part of the circuit giving you a problem.
I would then start disconnecting the components one by one (headlight, tail light, handlebar switches, computers, relays.....) checking the voltage at the battery.

Hello Bert,

Thanks again for the advice. yes, I shall do your suggestion. On top of it, I will recheck the "kill switch". It was dismantled, cleaned and reinstalled last week. This may create the short circuit.

Good luck to ...me

Hi Adiwan if you have not done so already I would remove and carefully dismantle the ignition switch (small parts) and clean the contacts. Measure the resistance of the contacts before and after cleaning just to be sure.

Hi Phil,

I think what you mean is the small green button on the left side handle bar, right?

I did dismantle the right handle bar switches, cleaned them and put them back together last week.

Latest development: I put a new Load Shed Relay...the dashboard is "alive" now. But I can not start the bike.
I took out the starter motor and hooked it up to a car battery, it does NOT run. So I believe I need to dismantle the starter motor and check and repair it.

Thanks again for continuing support, I shall update you with the progress.

Cheers.

I dismantled the starter motor and found out one of the magnets came off the housing. I re-glued it to the place and re-assembled the starter motor.

Then I connected to a strong battery to test run it. Horee.....it works. I put it back with optimism that the bike shall run when I put other bits of parts together.

Cheers.

Crazy Frog wrote: As the ground of the load shed relay coil is fed by the starter, I guess your starter has to be open and cleaned.

Amazing how the starter can affect the whole electrical on the K100. I had the same type of problem on my K75 and a good cleaning of the brushes killed the gremlins.
I did not mention it, but you could have tested the starter circuit without removing the starter.
This method works, but you have to be very careful not to press the starter button. Just put a good ground on the starter wire! This will provide the ground to the load shed relay.

Adiwan Djohanli wrote:Hi Phil,

I think what you mean is the small green button on the left side handle bar, right?

Could be a terminology or translation thing but I meant the switch in the middle with the key. It is amazing how much trouble that causes but I suspect you have found the problem with the starter. Heres hoping.

I wonder if anyone has tried rewiring the load shed relay by just running it to earth rather than through the damn starter motor. Granted it would not work as a load shed but who cares. Just turn the headlight off at the switch and turn it back on when the engine is running. Seemed to work pretty well on every other bike I have owned.

I wondered the same thing about the load shed grounding through the starter, Phil. Your idea would not work in some countries, however. In Canada, the headlight is required to come on with the ignition key so on the K100, the light switch is completely bypassed.

A bit of a strange one but I am aware that is the case in some countries but how long has it been that way?

My R100 was wired the same way and it was about a '78 model with no headlight on-off switch (initially) so an assumed European import. My R65 however was about the same vintage as the K100 but had an on-off switch.

I am pretty sure it could still be wired the same just not through the starter, just run it through a NC relay that opens when the starter button is pressed.

Hi Phil & Rob,

Thanks for the comments and inputs.

I expect to get "problems" with this bike from the start. Knowing that the bike is 1984model and I don't think the previous owners in Indonesia looked after her properly. I am a kind of perfectionist to the best of my ability

I am charging the battery now. I shall put back the battery later today Jakarta time of course. Then hopefully she will run.

Cheers guys.

I think care and patience will see you through so being a perfectionist will not hurt at all with bikes of this age.

I suspect humidity would be a big issue with electrical connections and you may have seen DeOxit mentioned once or twice so definitely worth the effort.

Last night I put back the battery and started the bike....happy it was all ok in starting and running it for about 30 minutes.

A new issue is starter button which is missing the top part, only the centre part left (small green tip).

Another thing is the engine was not running well. So next I must check all engine tuning parts/ components (Spark plugs, air filter, oil filter and lubrication).

Will do it over the week end as I need to work and travel during work days.

Cheers.

More fun and games but you definitely need the top to the starter as mine failed a while ago and it combined with the spring underneath actually disengages the starter circuit. You can still start it and ride but the effect is a little unusual so I got a s/h switch block from MotorWorks.

I still have the old one and believe it is repairable just have not tried yet.

Hello Guys,

Please allow me to report to you the progress of my bike.

For the last 3 days, last Sat-Sun and today My friends and I had worked on the bike. One is an experienced small Japanese bike, the other is also a motor bike enthusiast mostly working on old BSA and Harley Davidson.

All of us are puzzled and confused...seems that the problems jump from one to another.

The bike could start for about 15 - 20 minutes, and then stopped and could not restart.

Many components we had checked and each one of them is working well when we tested "independently".

1. Starter motor - 3 times
2. Cleaned spark plugs - 3 times
3. Load shed relay - 3 times
4. Cleaning the switch on right handle bar - 3 times
5. Dismantled, cleaned and re-installed the ignition key - twice
5. Dismantled, cleaned and re-installed injectors
6 Fuel pump was cleaned - 3 times

Every time we checked and jumped start, the bike ran well and suddenly stopped.

7. We dismantled the ECU, because we heard a "clung-clung" noise inside it. We found a capacitor (round - 1000 micro F came off). I remember this noise had been there from the beginning I bought the bike. this CAPACITOR is located behind pin no. 5 of ECU.

Is it the correct capacitor?? But we DO NOT have any reference. So we had to solder it back to its position.

We jumped start again...it ran again.

8. Cooling fan is bypassed using a manual switch..not yet dismantled

Please bear in mind, none of us is an automotive electrician. Therefore our ability to read the wiring diagram is very poor.

Up to now the bike can not run or start properly. On top of it here are the list of faulty "indicators"

a. Warning light, RED on dash board is ON all the time
b. Turn signal both right and left are OFF, but hazard light is ON
c. Speedo meter is NOT working
d. Low beam main light is sometime ON sometime OFF
e. Fuel pump is sometime ON sometime OFF
f. Starter motor is sometime ON sometime OFF
g. Load shed relay is sometime ON sometime OFF
h. Horn is sometime ON sometime OFF.

On Tuesday, we worked on the bike from 10 am till 23.30 pm. She was running ON and OFF. At present, we can not start the bike. When we turned ON the ignition key, NO clicking on the Load shed relay. With the key is ON, we pushed the starter switch..we only got clicking noise but the stater motor does not work.

Wow..wow..wow. So much problems with the bike.

Where shall I continue the repair???
How can I check the ECU?

Can you please help?
Any comment, input or advice shall be much appreciated.

Hopeless,
Adiwan. :arrow:

Adiwan,

When you said that you checked the starter motor, did you open it and cleaned it?
On my K75, I had a weird problem too. I even switched the starter but the electrical was crazy. I finally opened it and gave it a good cleanup and everything is fine now.

The bike is starting and then stopping when its hot. This is exactly the symptom of a bad HALL sensor.
If your are able to start your bike, start it and stop it a couple of times to be sure that it works.
You then stop the bike and take a hair dryer. Warm up the sensors and then try starting again (you can test it statically with a diode. See the FI troubleshooting page for the procedure). The Hall sensors are known to fail when hot.

Here is a test to check if the electrical problem comes from the starter:

First at no time you should push the starter button.
After turning the ignition ON, take a good size wire and ground the connection to the starter.
If when the starter is grounded everything is working on your instrument cluster, you just proved that the starter has a problem.
In normal operation, the wire going to the starter is bringing the negative 12v to the wiring loom. It is only conducting positive when you push the starter button.
Again, never push the starter button during this procedure.

Hello Bert,

Thanks for your fast advice. I appreciate very much.

We did take off the starter motor, dismantled and cleaned it. We are sure it works well. When ignition ON, we checked the wire using a test pen, connected to ground, test test pen's light is ON. We think it has +12V (???), we are puzzled about this. I shall re-check this according to your advice. However the the dashboard lights are ON when ignition ON. But when we push the starter button, the stater motor does not work, fuel pump Not work. We only hear "clicking" noise. I assume it is the noise from relays.

I shall check the HALL censor and report back to you later.

How about the ECU? I have strong suspicion that it had been "modified" (??)., especially because we found a loose capacitor 1000 micro Farad with its short wire poking out inside the ECU box. Obviously this loose capacitor can create lots of problems or short circuit when it moves. Is this capacitor the correct size?

Your advice is much appreciated.

Regards,
Adiwan.

When you turn the ignition key on the ON position, the headlight should turn ON too.
Does the headlight turns OFF when you push the starter button?
This is the function of the load shed relay. The load shed relay works in conjunction with the starter relay. If the starter relay is bad, the load shed relay will not work correctly.
Have you checked the starter relay?
If the PO had tried to start the bike when the battery was low, he may have burned the contacts of the starter relay. This is quite common on the K100.
You are talking about the ECU. An ECU (Engine Control Unit) controls injection and ignition...
The 1984 has 2 computers: the EFI and the ignition. Which one are you referring to?

Bert

Hello Bert,

When ignition ON the headlight is OFF all the time. It did ON twice when the light switch is turned ON. But now it is OFF even with the light switch ON. Strangely, the hi-beam is always ON when I turn ON the light switch.

I have not checked the starter relay. I will check it.

Regarding the ECU, I am referring to the unit under the sit.

Thanks and regards.

Hi Adiwan,

I don't need to add to Bert's excellent advise as he will steer you in the right direction.

What I will say though is to try and focus on one problem at a time as it is easy to go off at a tangent and then try and fix everything all at once BTDT too many times.

The best idea is to get one problem sorted, make sure it works then move on to the next one. I may be preaching to the converted but it is very easy to introduce another problem while fixing another.

A multimeter is also a better option than a test light in a lot of instances as I found some problems on mine which was evident with a reading of around 11v when I should have had 12.5.

Electrical diagrams take a while to get used to but if you can enlarge to like house plan size it makes a little more sense and the main thing is to work out which is connected to earth and which is connected to 12V.

Basically time and patience will see you through.

Hello Phil,

Thank you very much for the input / comment. yes you are correct, to do one thing at the time. I did that, but it seems that the problem keeps coming up after repairing or solving one.

I believe there is an easier approach to solve the problems, in other words an effective sequence or systematic way to handle these problems.

I shall keep you guys updated.

Thanking you for your kind attention.

Cheers.

Adiwan Djohanli wrote:
7. We dismantled the ECU, because we heard a "clung-clung" noise inside it. We found a capacitor (round - 1000 micro F came off). I remember this noise had been there from the beginning I bought the bike. this CAPACITOR is located behind pin no. 5 of ECU.

Yes there is a capacitor between pin #5 and pin #9. Check the internal schematic here (available in the download section)

Adiwan Djohanli wrote:When ignition ON the headlight is OFF all the time. It did ON twice when the light switch is turned ON. But now it is OFF even with the light switch ON. Strangely, the hi-beam is always ON when I turn ON the light switch.

Just give me a bit of time to think about it.

Bert

HI Bert,

Thank you very much for the Schema of LE-Jetronic. DO you have the value of each component such as the resistors and capacitor?

Cheers.

Adiwan Djohanli wrote: DO you have the value of each component such as the resistors and capacitor.

I am sorry, this is the only schematic that I could find. At least it shows you where the capacitor should be re-solder.

Hi Bert,

Thanks again.

I will do some work on the bike again this week end.

Cheers.

Hello Bert & Guys,

The bike is still NOT running, can not start.

The present situation/condition:
- Turn on ignition switch 1X, small front light and tail light are ON, dash board lights are OFF.

- Turn on ignition switch 2X, next after 1X. Small front light and tail light are OFF, dash board lights are ON. There is NO click noise on Load shed relay and other relay. I heard the click noise of relays when turn 2X and she started before.

- With ignition switch ON (2X), I pushed the starter button. I can hear the fuel pump runs and clicking noise of starter relay. But the starter motor does NOT run.

Before this "dead" situation, I did have the bike running "well" for 25-30 minutes.

Can you please advice me what next to check?
I think the load shed relay must click when I turn ignition switch ON (2X). But now there is no click noise any more.

I want to check Temperature sensor, Temperature sensing sw unit and HALL sensor, but I do not know where they are located. Please advice.

I am very sorry for so many questions.

Your advice, guidance and comment are much appreciated.

Hopeless at present....

No apologies required and I will just say a couple of things.
Ignition switch in first position is normal i.e. park lights
Ignition switch in second position (assuming you have a headlight switch) is also normal as instrument lights should be on and all lights off. If you do not have a separate headlight switch then that is an issue.

To get power to the starter you need Ignition switch in no2 position, kill switch in central position, bike in neutral or clutch in. Any one of these not working properly will not allow the starter relay to engage hence no starting.

If you can definitely determine the starter relay is engaging then it comes down to the relay itself i.e burnt or contacts not engaging or the starter motor itself.

The starter relay can be opened (carefully) and you can check if the contacts are engaging and it only takes about 6 volts to activate it but ideally connect power to the coil of the relay and put a meter across the starter terminal just to make sure it is doing the right thing.

Adiwan Djohanli wrote: - With ignition switch ON (2X), I pushed the starter button. I can hear the fuel pump runs and clicking noise of starter relay. But the starter motor does NOT run.
I think the load shed relay must click when I turn ignition switch ON (2X). But now there is no click noise any more.

When you turn the ignition switch ON (2X), the load shed relay should be energized. The +12v goes from the ignition switch to the kill switch and to pin 86 of the load shed relay. Pin 85 of the load shed relay gets the -12v from the starter.

Have you tried to jump start the starter? With the ignition OFF? Get the +12v from the battery and apply it directly to the starter. It should turn.
Even if you opened the starter to clean it up, you may have missed a cut in one of the coil of the motor and this will prevent the load shed relay to engage.
You have to do this test.
Please report what you found.

Bert

Phil & Bert,

Thank you very much for your comment and advice.

The bike has a head light switch, on the right handle bar. Thsi switch has 2 positions, 1st is for small and tail light, 2nd position activates the head light. This switch is NOT functioning now so as the horn.

I shall carry out those tests tomorrow during the day. Then I will report back to you.

Thanks again.

And this is certainly because of the load shed relay not working. The most probable cause is a problem with the starter not conducting the ground to the coil of the load shed relay.
From the description of your problem, I suspect that something is wrong with the starter.

Bert

Hi Bert,

I will re-test the starter motor as advice.

I experience that when Load shed relay is not working, all dash board light were OFF. But this time the all dash board lights are ON...(???).

Hope you can give me explanation about this.

Thanks again and regards.

Sometimes, having the bike in 5th gear and rocking the back wheel back and forth will just move the starter enough to enable the conductivity of the ground to the coil of the load shed relay.

Hi Bert,

I will do the tests as advice soon and I shall report back to you.

Your kind attention is much appreciated.

Regards.

Hi Bert, Phil & Others,

It is 02.25am Sat early morning here. I just finished my shower after spending the night with the bike.

I jumped started the starter motor (still on the bike), it did not turn. So I took out, dismantled, checked and cleaned it. The carbon brushes and the wires are still good. Then I cleaned the copper part of contact points for the brushes.

Then re-assembled the starter motor, tested the run on a battery, it worked. I re-installed the starter motor, not yet connected the wire from the relay. Jumped started again, it could still turn. So I connected the wire.

Next I started again using a car battery. It turned strongly, but the engine could not run. I took off the spark plugs...they were wet. Cleaned them up and re-installed.

The bike ran after 3 Starts....well done. Left it running for about 10 minutes, switched it off and switched ON again... she ran reasonably well.

Thanks to Bert, Phil and other members who have guided and advised me on this matter.

Bert is correct, it was problem with the starter motor....somehow not working properly.

Later today I will re-connect the wire of cooling fan to standard scheme and will do road test. I will update you with the outcome.

Once again thank you Bert, Phil and other members.

Best regards.

Good news, well done.
Regards,
K-BIKE

K-BIKE wrote:Good news, well done.
Regards,
K-BIKE

Hi K-BIKE,

Thank you for the encouragement. I still have many things to fix on the bike such as turning indicators, speedometer and cooling fan to name a few.

Next time I visit my kids in Hamilton, I shall meet you in Auckland.

Have a nice week end.

I shall look forward to that!
Regards,
K-BIKE

The important thing is making progress as up until that point it can get very depressing so persistence has paid off and you can relax for a while.

Granted as you mentioned there are other problems to solve but getting a major one behind you will make the others easier and may have helped cure them as well.

Hi Phil,

It has paid off. I also learn that the starter motor is very similar with a local produced Honda "Tiger", 200cc. It is made by Nippon Denso. However I need to checked further the position for mounting to the engine.

I am going to check the thermostat, I suspect it had been removed...then I need to find a replacement of it.

I keep "paddling" and "paddling"....


Have a nice week end Phil,

The starter theory is interesting although probably not that unusual and if you trawl through some of the posts you will find a topic which refers to different thermostats available.

Enjoy the rest of the weekend.

The bike could start well 3-4 times yesterday using a newly recharged 24A Yuasa battery. But the engine would not run..until the battery was flat.

I hooked up jumper lead to the battery in my car...then the engine ran after 2 start. I rode the bike around town for half hour. It was fine.

The cooling fan was ON after about 10 minutes of ride. Of course I had re-wired back to its original electrical scheme and I installed a Toyota thermostat - 76.5 C.

This morning I tried to start the bike again, but after 2 pushes on the stater button, the battery ran flat. Again I jumped started the bike..it ran pretty smooth.

After about 10 minutes of running idle at 950 rpm on the meter, the fan turned ON automatically.

She is getting better now. But I shall create a new topic regarding the battery issue.

Thanks guys for all your kind attentions, advices and comments.

Best regards.

Hi guys

I am having a similar problem on my 89 K75s. Bad starting etc. Eventually traced it down to a bad connection from the battery positive terminal (good at the terminal, but bad about 2 inches down which was covered with insulation tape). Fixed that, but it created another problem. Started first time, but the starter motor doesn't turn off (even with the key out and the kill switch in off position). Indicators and horn don't work either. Checked the Starter Relay since I have heard this is often the problem if it sticks. Relay is fine, can see it going on and off when i hit the starter button. But problem persists. Any ideas? I thought perhaps the starter motor itself, or the load sharing relay (but these are just the first 2 that come to mind). It's been quite a while since I did fault diagnosis on a BM (back in the 70s when the electronics weren't as sophisticated as they are on a late 1980s bike.

Hi Ramadge,
Start another thread otherwise yours will get lost in Adiwan's thread and technically is a hijack of his problem. As a final point the relay contacts must be stuck even if the armature of the relay goes up and down because unless you have rewired it that relay is in circuit with the starter - no closed contacts starter cannot run.
Regards,
K-BIKE