Are you using jumper leads with your car battery?

Are you confident they're good?

daveyson wrote:Are you using jumper leads with your car battery?

Are you confident they're good?

Tried Jumper cables and also other wires. Starter motors work well when disconnected from engine.

It's not looking good. What's the history, like the last ride was good, then the next day it wouldn't start? Oil and coolant good, stuff like that. Should probably turn easier without spark plugs, at least the crank cover is easy to get to.

daveyson wrote:It's not looking good. What's the history, like the last ride was good, then the next day it wouldn't start? Oil and coolant good, stuff like that.  Should probably turn easier without spark plugs, at least the crank cover is easy to get to.

This recent winter months (temp 6-16°C here) I ride only once a week, but no problems at all. Parked for two weeks and starting issue showed up when I wanted to start.   First connected battery charger and than started to investigate.   No oil problem (never consumed nor leaks and also cooling water is always on level.    (some drops of oil entered in cooling system due to consumed seals in water\oil pump that I am servicing now)

Gergely wrote:

daveyson wrote:Are you using jumper leads with your car battery?

Are you confident they're good?

Tried Jumper cables and also other wires. Starter motors work well when disconnected from engine.

They don't need much power to do that. They just spin. 

But they need lots of power to turn over in the engine.

You are having the same problem using different starters. 

Something is pointing to bad batteries not having enough current, bad connections or bad cables not passing enough current or an issue in the sprag clutch. 

Have you tested the batteries, as in load tested them?
Have you measured or can you measure the current draw at the starter as you are trying to start the bike?
Have you done anything else to the bike that might affect turning the engine over?

92KK 84WW Olaf wrote:

Gergely wrote:

daveyson wrote:Are you using jumper leads with your car battery?

Are you confident they're good?

Tried Jumper cables and also other wires. Starter motors work well when disconnected from engine.

They don't need much power to do that. They just spin. 

But they need lots of power to turn over in the engine.

You are having the same problem using different starters. 

Something is pointing to bad batteries not having enough current, bad connections or bad cables not passing enough current or an issue in the sprag clutch. 

Have you tested the batteries, as in load tested them?
Have you measured or can you measure the current draw at the starter as you are trying to start the bike?
Have you done anything else to the bike that might affect turning the engine over?

Batteries are ok (tested 3, even direct cables from car battery with car engine in operation, charging battery in the meanwhile). Tested different cables/wires, current arrives to starter motor.   Tested 3 starters (original and 2 used but bought from Germany bike shop - guaranteed).       Sprag clutch semms doing its function.  Engine is moving.     I'd think some extra friction in engine or sprag clutch..     How much hand power you need to turn engine by rear wheel? I can turn it using 2 hands in 4-5th gear, but not in 1-2nd. Sounds more or less normal?

Is there any difficulty mounting the starter motors? The joint surface should be clean but no gasket or sealant.

Are you happy all 3 starters are good? Just because they are used does not mean they are good. They could all have the same fault too.

Take out all of spark plugs, mount the starters one at a time and use the starters to turn the engine over. Does it turn over ok?

92KK 84WW Olaf wrote:Is there any difficulty mounting the starter motors? The joint surface should be clean but no gasket or sealant.

Are you happy all 3 starters are good? Just because they are used does not mean they are good. They could all have the same fault too.

Take out all of spark plugs, mount the starters one at a time and use the starters to turn the engine over. Does it turn over ok?

Everything visible is clean like as new components. All 3 starters could be faulty but low possibility I think. Spark plugs out and water|oil pump as well.  Same issue, engine does not tuturn over by s.motors

When you say the batteries (car or bike) were tested was that via a load test device?

If you connect a a meter set to volts across the battery what is the standing voltage.

Then with it still connected, try to jump start the bike again. What is the voltage reading on the battery during the attempted start?

Mike

+1 be good to know Voltage across battery, and while cranking, and at the starter post while cranking.

"~ can turn by hand in 5th is normal? "
I think so with spark plugs in.

Can you push it? Can you push (roll, bump) start it?

Oil and water pump is removed?????

Is anything else removed?

92KK 84WW Olaf wrote:Oil and water pump is removed?????

Is anything else removed?

Removed for inspection and rebuilding seals....just while bike can not be used because of non starting issue.

daveyson wrote:+1 be good to know Voltage across battery, and while cranking, and at the starter post while cranking.

"~ can turn by hand in 5th is normal? "
I think so with spark plugs in.

Can you push it? Can you push (roll, bump) start it?

Voltage 12,5V   but I must try while cranking...                  Even if I can turn wheel by hand in 4-5th gear, I could not bump start it neither in 2-3-4-5 gears. Tyre slips/block very soon.

I'll guess it was much easier to turn the wheel with the spark plugs out.

You need a steep hill and a fair bit of weight to picture a roll start.

I'd try a better battery.

daveyson wrote:+1 be good to know Voltage across battery, and while cranking, and at the starter post while cranking.

"~ can turn by hand in 5th is normal? "
I think so with spark plugs in.

Can you push it? Can you push (roll, bump) start it?

Battery has 12,8 V.    In fase of starting attempts (attached to starter motor installed that does not move) goes to 4-5 V or seems even to 0 V.         Current measured with starter motor spinning outside seems 12-15 Amp. meanwhile in fase of starting attempts (attached to starter motor that does not move) goes up to 120 -180 Amp.  At least what I measured.

Or just a bad contact somewhere between the donor battery and the starter terminal.

Mike

92KK 84WW Olaf wrote:In fase of starting attempts (attached to starter motor installed that does not move) goes to 4-5 V or seems even to 0 V. 




???? Dud battery????

This is with original bike battery....that is discharging because bike is dead.     But even with 100% good battery (direct cable from80 Ah new van battery with engine in operatoperation) the result is the same = no turn over.         I can retry and make measurements with the van's battery.

If you remove the spark plugs, will the battery crank the engine? With the spark plugs removed, can you easily crank the engine by rotating the rear wheel?

Laitch wrote:If you remove the spark plugs, will the battery crank the engine? With the spark plugs removed, can you easily crank the engine by rotating the rear wheel?

spark plugs removed (and also oil|water pump x rebuilding) and by rear wheel in 4_5th gear engine can be rotated by hand. Not very easy but with 2 hands doable.         I think starter relay (even if click can be heard on starting) has something  faulty like condenser that shpuld give extra power at starting.

Gergely wrote:

Laitch wrote:If you remove the spark plugs, will the battery crank the engine? With the spark plugs removed, can you easily crank the engine by rotating the rear wheel?

spark plugs removed by rear wheel . . . in 4_5th gear engine can be rotated by hand. Not very easy . . .

This could be a mechanical problem rather than an electrical one.

Is it possible the oil pump is the cause of the engine not turning over? Incorrect shaft change causing the engine to be 'locked'? Did you get a replacement shaft for the pump? Is it the correct shaft, or indeed the correct seals? Is it possible the engine oil is severely overfilled? You do need to eliminate any of these possibilities.

Is it possible there is an issue in the mounting of the starter motors causing them not to turn?

Is it possible the sprag clutch has suffered some issue preventing it form turning over?

For all of the above removing the plugs and turning over by hand should give some answer.

I am struggling to see the cause but I am still not fully convinced the starter is actually getting a perfect electrical connection to turn over. A new battery is not always good either. 

Using the remote battery seems to isolate bike related problems but maybe this might be an idea but don't so it until someone else says its ok- Disconnect the bike battery and the ICU and the FICU, mount the starter, connect your spare battery live to the starter live supply and the spare battery earth to the frame. The moment you connect the earth the starter should turn the engine over.

I have seen many instances of jump leads stored in a car or van for an age failing because of humidity related corrosion on the clamps causing resistance at the usually hidden and insulated galvanised steel clamp/copper wire clamped joint. Getting meter readings at different points can tell you if this happening. 

I recall another thread here that had a similar type of debate going on after a rear main seal replacement and other seals replaced had resulted in the bike also being locked and only finally resolved after the the K owner eventually revealed he had actually opened the gearbox to replace a seal normally replaced from outside and 'some little bit fell out but it went back together fine'. A gearbox replacement solved it for him.

My money is still on the starter not getting a good electrical connection.

Hi Gergely,

Post #70. There is no capacitor/condenser to provide any extra surge for starting.

Mike

92KK 84WW Olaf wrote:Is it possible the oil pump is the cause of the engine not turning over? Incorrect shaft change causing the engine to be 'locked'? Did you get a replacement shaft for the pump? Is it the correct shaft, or indeed the correct seals? Is it possible the engine oil is severely overfilled? You do need to eliminate any of these possibilities.

Is it possible there is an issue in the mounting of the starter motors causing them not to turn?

Is it possible the sprag clutch has suffered some issue preventing it form turning over?

For all of the above removing the plugs and turning over by hand should give some answer.

I am struggling to see the cause but I am still not fully convinced the starter is actually getting a perfect electrical connection to turn over. A new battery is not always good either. 

Using the remote battery seems to isolate bike related problems but maybe this might be an idea but don't so it until someone else says its ok- Disconnect the bike battery and the ICU and the FICU, mount the starter, connect your spare battery live to the starter live supply and the spare battery earth to the frame. The moment you connect the earth the starter should turn the engine over.

I have seen many instances of jump leads stored in a car or van for an age failing because of humidity related corrosion on the clamps causing resistance at the usually hidden and insulated galvanised steel clamp/copper wire clamped joint. Getting meter readings at different points can tell you if this happening. 

I recall another thread here that had a similar type of debate going on after a rear main seal replacement and other seals replaced had resulted in the bike also being locked and only finally resolved after the the K owner eventually revealed he had actually opened the gearbox to replace a seal normally replaced from outside and 'some little bit fell out but it went back together fine'. A gearbox replacement solved it for him.

My money is still on the starter not getting a good electrical connection.

Thanks!  So:    oil/water pump is not an issue as it is still not installed.   In any case engine turns over by  hand/rear wheel (spark plugs are removed).    Sprag clutch seems OK (Right spins|Left engages to engine).         Starter motor can not be mouted badly.   Connections are clean and tight.    Tried 3 batteries even 80Ah in car in operation=charging well. With live|direct connections from battery does not turn over (starter spins well when dismantled).    Engine or gearbox has never been opened, turns everything well together(by hand).
Electrical issue is still the most likely. I think starter relais Bosch 0 332 002 161 or something in near connection will have some strange "weakness" issue...I'll keep investigate..

If oil pump not installed you have no oil and no coolant in the engine? It had not occurred to me the pump remained off the engine like that. 

Can anyone say if that makes any difference mechanically? 

Its very possible to destroy the starter relay trying to start the bike if the battery is not fully charged....BUT you said you used the car battery and got the same result. Some posts are not too clear, is the car battery simply used as a booster or did you connect direct to the starter? If you simply used it as booster then a defective relay could do it. So can a defective starter, a bought replacement can have an identical defect. And so can the second replacement as my son discovered so just because you have 3 there is no guarantee they are all good. But I believe so can a defective load shed relay. 

If at all times you used the car battery as a booster and you have no mechanical problem you are back to the problem being in layman's terms along the route from the + terminal on the battery to the starter relay, through the relay on to the starter and through the starter back to earth through the casing into the gearbox and from there by the earth wire on the lug above the gear lever back to the battery - terminal  Have you cleaned all the contact points? 

Put the starter in, connect the battery - negative to earth as it should be, then get a wire and touch the + live direct to the starter + terminal terminal. Leave the plugs out. The starter should turn the minute you touch the live supply. Put the plugs in and repeat. 

K experience is that the most frequent causes are poor battery, defective starter relay [often caused by poor battery], poor electrical contact/terminal contact and concealed break in a cable.

If you really are getting ~150 Amps (you express some doubt) sadly, that makes me think your battery, and electrical system, is good.

I'm with Laitch, it's looking mechanical. Unfortunately it's not looking good for the engine. I remember the wheel turns easy in neutral, I'd check if also easy in gear with clutch pulled in, don't remember.

Some other things that point in the same direction, the starter only turns the engine with the plugs removed and with help to start. I think your car battery test was directly to the starter.

But 4 Volts (you also mention 0 Volts?) at cranking is really low.

How many Volts do you have at the starter positive electrical post with the start button pressed?

From post 65

Battery has 12,8 V.    In fase of starting attempts (attached to starter motor installed that does not move) goes to 4-5 V or seems even to 0 V.         Current measured with starter motor spinning outside seems 12-15 Amp. meanwhile in fase of starting attempts (attached to starter motor that does not move) goes up to 120 -180 Amp.  At least what I measured.


Your thoughts?

I've done a stall test on my brick, it came up ~100 amps (a cheap but not so accurate hold over type) so that points to excessive mechanical resistance.

But the 4 Volt bit. I spose Gergely has just done a load test on the battery, and it's failed?

But the wheel won't turn when attempting a roll start?

I'll go back to hoping the battery isn't good enough.

92KK 84WW Olaf wrote:If oil pump not installed you have no oil and no coolant in the engine? It had not occurred to me the pump remained off the engine like that. 

Can anyone say if that makes any difference mechanically? 

Its very possible to destroy the starter relay trying to start the bike if the battery is not fully charged....BUT you said you used the car battery and got the same result. Some posts are not too clear, is the car battery simply used as a booster or did you connect direct to the starter? If you simply used it as booster then a defective relay could do it. So can a defective starter, a bought replacement can have an identical defect. And so can the second replacement as my son discovered so just because you have 3 there is no guarantee they are all good. But I believe so can a defective load shed relay. 

If at all times you used the car battery as a booster and you have no mechanical problem you are back to the problem being in layman's terms along the route from the + terminal on the battery to the starter relay, through the relay on to the starter and through the starter back to earth through the casing into the gearbox and from there by the earth wire on the lug above the gear lever back to the battery - terminal  Have you cleaned all the contact points? 

Put the starter in, connect the battery - negative to earth as it should be, then get a wire and touch the + live direct to the starter + terminal terminal. Leave the plugs out. The starter should turn the minute you touch the live supply. Put the plugs in and repeat. 

K experience is that the most frequent causes are poor battery, defective starter relay [often caused by poor battery], poor electrical contact/terminal contact and concealed break in a cable.

Oil pump is dismantled (after ignition problems) for extra service on sealings.  So with engine that does not operate it is only a help for engine to turn over.   Same for spark plugs taken out.
Car battery was used as booster, stand alone, connected to 220V charger and even with car in operation, connected to bike's circuit and also with direct wire (so, excluding any possible fault in bike relays and connections) to starter motor.   No turn over.        I think all options tried.   
 Still all 3 starter motors can have the same fault: being weak to turn over and work well without load.

Not sure if you've checked this but if you are getting a voltage drop down to 4-5 Volts when you are trying to start the bike, then there is likely something wrong with your cables. You are getting a short somewhere in the starter circuit. Measure the voltage at the battery and then measure the voltage at the positive cable at the solenoid. Use the batteries own ground post for the negative cable. They should have exactly the same voltage. If you have any voltage drop between these two readings then you have corrosion in a cable. That voltage drop is likely not enough to activate the starter solenoid as well. Not sure if I read that the solenoid would click or not. Maybe its the starter solenoid.

A cable with corrosion ( on the inside and you can't see it ), once it comes under load, ( when you push the starter button ) will not pass enough voltage to the solenoid/starter to start the bike. I had this happen on on old gold wing. Replaced the battery and still wouldn't start. If I boosted it with a car battery it would start and run. Replaced the positive cable from the battery to the solenoid, and bike started.

My two cents for what they are worth.

cycleman wrote:Not sure if you've checked this but if you are getting a voltage drop down to 4-5 Volts when you are trying to start the bike, then there is likely something wrong with your cables. You are getting a short somewhere in the starter circuit. Measure the voltage at the battery and then measure the voltage at the positive cable at the solenoid. Use the batteries own ground post for the negative cable. They should have exactly the same voltage. If you have any voltage drop between these two readings then you have corrosion in a cable. That voltage drop is likely not enough to activate the starter solenoid as well. Not sure if I read that the solenoid would click or not. Maybe its the starter solenoid.

A cable with corrosion ( on the inside and you can't see it ), once it comes under load, ( when you push the starter button ) will not pass enough voltage to the solenoid/starter to start the bike. I had this happen on on old gold wing. Replaced the battery and still wouldn't start. If I boosted it with a car battery it would start and run. Replaced the positive cable from the battery to the solenoid, and bike started.

My two cents for what they are worth.

Cables are all OK and connections clear. Battery is OK: 12V. With direct wires -> starter motor runs without load but does not turn over when installed!  With bike's circuit happens as follows -> By ignition key turn ON: "click" of load shredder relay can be heared (but only if starter motor is connected otherwise not...is this normal?)     At start button push -> approx. 8 V arrives to starter relay solenoid to activate it (86-87).  Starter relay activates (closes 30-89) and starter motor spins when not installed (without load.) but starter motor does not turn over when intalled and starter relay makes a buzzing noise! In both cases (starter installed and still or taken out and turns) voltage drops from 12 V to 7-8 V approx and 16 Amp of current is measured on starter motor.      A short or similar on bike mass|ground could be a problem, but with direct wiring from battery the sad situation is the same.

Options

1 Battery is toast.
2 Starters are toast
3 Mounting of the starters is an issue.
4 Earth connections are an issue.

Buzzing noise=  overload due to reduced voltage.

92KK 84WW Olaf wrote:Options

1 Battery is toast.
2 Starters are toast
3 Mounting of the starters is an issue.
4 Earth connections are an issue.

Buzzing noise=  overload due to reduced voltage.

I'll retry
1 - with 3rd battery in car, with car in operation (charging).
2 - n°3 starters tried with the same result
3 - mounting is not an issue I think
4 - checking earth connections can be a good thing...I will work on it

Relay is new, so buzz for low voltage issue si probably the case.

Still do not understand why doesn't turn over by direct wiring  BATT - > Starter

I'll report....

A lot of stuff is pointing to the starter. Bad starter can destroy the relay.

I would mark the ends of the starter so you are sure to reassemble it correctly, open it and put the photos up here. Its only 2 long bolts either side that go the full length. 

There are 2 things in it to check out.

The carbon brushes, do a close op photo.
The copper that the brushes rub against. Don't clean them, leave them as they are and photo them.

Gergely wrote:Still do not understand why doesn't turn over by direct wiring  BATT -> Starter

Describe your direct wiring.

92KK 84WW Olaf wrote:A lot of stuff is pointing to the starter. Bad starter can destroy the relay.

I would mark the ends of the starter so you are sure to reassemble it correctly, open it and put the photos up here. Its only 2 long bolts either side that go the full length. 

There are 2 things in it to check out.

The carbon brushes, do a close op photo.
The copper that the brushes rub against. Don't clean them, leave them as they are and photo them.

I serviced starter 2 yrs ago (new brushes etc).
Now I have other 2 starters, bought used but guaranteed from German shop.  All running perfect without load.

Laitch wrote:

Gergely wrote:Still do not understand why doesn't turn over by direct wiring  BATT -> Starter

Describe your direct wiring.

Can you do this one?

I have struggled too trying to understand how you did it.

92KK 84WW Olaf wrote:

Laitch wrote:

Gergely wrote:Still do not understand why doesn't turn over by direct wiring  BATT -> Starter

Describe your direct wiring.

Can you do this one?

I have struggled too trying to understand how you did it.

Good, full charged Battery NEGATIVE connected by 1 wire directly to bike frame clutch area.   From Battery POSITIVE another wire directly to starter motor positive connection (with bolts).      This should start motor (as it does when it is dismounted (no load). At least if there is no special circuit to give extra power for starting (condenser or similar) in the bike.

I hate to say it, but you have to bite the bullet and pull the sprag out and service it. It isn't going to to repair itself while we go back and forth on all the stuff that you say is working properly.

Gergely wrote:

cycleman wrote:
A cable with corrosion ( on the inside and you can't see it ), once it comes under load, ( when you push the starter button ) will not pass enough voltage to the solenoid/starter to start the bike. I had this happen on on old gold wing. Replaced the battery and still wouldn't start. If I boosted it with a car battery it would start and run. Replaced the positive cable from the battery to the solenoid, and bike started.

My two cents for what they are worth.

Cables are all OK and connections clear. Battery is OK: 12V. With direct wires -> starter motor runs without load but does not turn over when installed!  With bike's circuit happens as follows -> By ignition key turn ON: "click" of load shredder relay can be heared (but only if starter motor is connected otherwise not...is this normal?)     At start button push -> approx. 8 V arrives to starter relay solenoid to activate it (86-87).  Starter relay activates (closes 30-89) and starter motor spins when not installed (without load.) but starter motor does not turn over when intalled and starter relay makes a buzzing noise! In both cases (starter installed and still or taken out and turns) voltage drops from 12 V to 7-8 V approx and 16 Amp of current is measured on starter motor.      A short or similar on bike mass|ground could be a problem, but with direct wiring from battery the sad situation is the same.

The only sound I will hear on my 86 when I turn the key on is the fuel pump. It runs very briefly, then silence, until I push the starter button. You shouldn't have any buzzing noises coming from a relay. The relay is likely shot. With the voltage numbers you are showing, 8 Volts at the relay are never going to turn the starter. Somewhere you have a short, when the starter comes under load, ie: with the starter installed & engaged in the sprag clutch system. That explains why the starter will turn when not installed in the bike.  My under standing of the sprag clutch causing issues is that the installed starter will spin, but the sprag won't engage. I guess its always possible that the sprag might have totally seized up, but I haven't read about that being a big issue with the sprags in our bikes. It still looks like an electrical issue, but hell, I've been wrong before. If you did any recent work on the bike, go back and trace your steps.

cycleman wrote:

Gergely wrote:

cycleman wrote:
A cable with corrosion ( on the inside and you can't see it ), once it comes under load, ( when you push the starter button ) will not pass enough voltage to the solenoid/starter to start the bike. I had this happen on on old gold wing. Replaced the battery and still wouldn't start. If I boosted it with a car battery it would start and run. Replaced the positive cable from the battery to the solenoid, and bike started.

My two cents for what they are worth.

Cables are all OK and connections clear. Battery is OK: 12V. With direct wires -> starter motor runs without load but does not turn over when installed!  With bike's circuit happens as follows -> By ignition key turn ON: "click" of load shredder relay can be heared (but only if starter motor is connected otherwise not...is this normal?)     At start button push -> approx. 8 V arrives to starter relay solenoid to activate it (86-87).  Starter relay activates (closes 30-89) and starter motor spins when not installed (without load.) but starter motor does not turn over when intalled and starter relay makes a buzzing noise! In both cases (starter installed and still or taken out and turns) voltage drops from 12 V to 7-8 V approx and 16 Amp of current is measured on starter motor.      A short or similar on bike mass|ground could be a problem, but with direct wiring from battery the sad situation is the same.

The only sound I will hear on my 86 when I turn the key on is the fuel pump. It runs very briefly, then silence, until I push the starter button. You shouldn't have any buzzing noises coming from a relay. The relay is likely shot. With the voltage numbers you are showing, 8 Volts at the relay are never going to turn the starter. Somewhere you have a short, when the starter comes under load, ie: with the starter installed & engaged in the sprag clutch system. That explains why the starter will turn when not installed in the bike.  My under standing of the sprag clutch causing issues is that the installed starter will spin, but the sprag won't engage. I guess its always possible that the sprag might have totally seized up, but I haven't read about that being a big issue with the sprags in our bikes. It still looks like an electrical issue, but hell, I've been wrong before. If you did any recent work on the bike, go back and trace your steps.

If you are hearing your fuel pump the moment you turn on the ignition on an 86 K then you have an issue. Its not energised on 2v engines until you press the start button.

There have been a couple of incidences of sprag clutches but it's small and its far far more likely you are looking at some electrical issue.

Buzzing relay has been mentioned and as you say a bad sign but some of us have asked exactly how the car battery was connected. Not yet responded to. I asked to do a test connection direct from the battery positive to the starter in position. Not yet done. I asked to do same using the car battery. My simple logic tells me that if they are all ok it means starter is good and relay is good, problem is battery. If not ok it suggests starter is bad.

Some meter readings given are also suggesting battery is the issue but also suggest it may be the starter. Starter relay is possible but so also the the Load Shed Relay. Meter reading of 150Amps in theory is ok but apparently it was only about 4,5 volts. My imperfect physics suggests that's equivalent to 50 amps at 13.5 volts and that's not ok. 

I don't think I am going to put any more posts in this thread but will keep an eye out.

Hi Olaf,

Post 88 suggests that the jumper cables were connected direct t o the bike frame and starter, so this would exclude the rest of the bikes circuit.

Something strange is certainly going on.

Mike

Everything electrical connected to the starter is perfect. He needs to pull the sprag and the output shaft.

mike d wrote:Hi Olaf,

Post 88 suggests that the jumper cables were connected direct t o the bike frame and starter, so this would exclude the rest of the bikes circuit.

Something strange is certainly going on.

Mike

Mike,

I agree 100%. My concern had been to isolate the bike electrics as a potential cause.

And Point Seven Five says pull sprag and output shaft. I agree too. 

But for the sake of it and the easy quick effort I would open and check the starter. Happened my son having a fault, original plus 2 replacement parts had the same identical and known fault and K starters do go faulty.

Gergely asserts that when the starter is spinning in the direction opposite of sprag engagement, the freewheel disengages the sprags in the clutch and spins freely on the auxiliary shaft as it should. When the starter is spinning in the correct rotation for engagement, the freewheel locks with the sprag clutch and attempts to rotate the auxiliary shaft. The problem is that not enough force can be applied to rotate the crankshaft easily once the sprag clutch is locked for shaft rotation. This has been the case with three different starters. He has observed that considerable effort has been required to rotate the crankshaft even when the spark plugs have been removed.

Although all this seems to be leading to the destination Point-Seven-five indicates, there are additional explorations to be considered that do not involve removing the driveline. Among them is removing the alternator to determine if its shaft has seized or its drive cup is obstructing auxiliary shaft rotation somehow. Another is removing the crankcase cover then inspecting each connecting rod for deformation that might be creating enough friction to slow crankshaft rotation. A third could be a leak-down test or endoscopic inspection of the combustion chambers to determine if something is restricting piston movement in one of them. After that, it's disassembly time.

Maybe he's just having a bad dream, we're tangled in its matrix, things are really less complicated than they seem, and we'll all have a good laugh when we awaken. 

This buzzing sound is a useful symptom. To me that means an electrical fault. It should be one solid click. You might have an earth failure at 85, power fail at 86, or (unlikely) both, or the relay itself.

The direct battery test almost bypassed everything, except the earth path, since you connected earth to the bike frame. I'd repeat the test and connect earth to the starter body and see if it then turns.

Just because you used two or three batteries, that doesn't mean the batteries are good. Even if the battery measures 12.8 Volts, it might not be capable of providing enough Amps.

With the starter clamped and stable, lever a piece of wood to try to prevent it from spinning, if you can (with a good battery) the starter is no good, try another one.

If you can turn the wheel with your hands you should be able to roll start it, I can't picture this good.

Gergely wrote:

92KK 84WW Olaf wrote:

Laitch wrote:
Describe your direct wiring.

Can you do this one?

I have struggled too trying to understand how you did it.

Good, full charged Battery NEGATIVE connected by 1 wire directly to bike frame clutch area.   From Battery POSITIVE another wire directly to starter motor positive connection (with bolts).      This should start motor (as it does when it is dismounted (no load). At least if there is no special circuit to give extra power for starting (condenser or similar) in the bike.

Have you tried running the negative from the car battery direct to the starter? Maybe there is a poor connection to the frame. When you are testing off the bike you are obviously connecting to the starter, so its not the same circuit.

EDIT: sorry just saw daveyson said the same thing.

No need for a sorry when offering help. With two people pointing to the same spot, it's less likely to be overlooked, so that's a good thing. I know what you mean though, a few times I've posted the same time as someone else and feel like I've rudely spoken over the top of somebody (but I don't choose the edit cause once I lost a huge reply doing that)  Help can easily be overlooked and overwhelming sometimes.

I'm with Laitch, this is becoming like another head spinner.

Laitch wrote:Gergely asserts that when the starter is spinning in the direction opposite of sprag engagement, the freewheel disengages the sprags in the clutch and spins freely on the auxiliary shaft as it should. When the starter is spinning in the correct rotation for engagement, the freewheel locks with the sprag clutch and attempts to rotate the auxiliary shaft. The problem is that not enough force can be applied to rotate the crankshaft easily once the sprag clutch is locked for shaft rotation. This has been the case with three different starters. He has observed that considerable effort has been required to rotate the crankshaft even when the spark plugs have been removed.

Although all this seems to be leading to the destination Point-Seven-five indicates, there are additional explorations to be considered that do not involve removing the driveline. Among them is removing the alternator to determine if its shaft has seized or its drive cup is obstructing auxiliary shaft rotation somehow. Another is removing the crankcase cover then inspecting each connecting rod for deformation that might be creating enough friction to slow crankshaft rotation. A third could be a leak-down test or endoscopic inspection of the combustion chambers to determine if something is restricting piston movement in one of them. After that, it's disassembly time.

Maybe he's just having a bad dream, we're tangled in its matrix, things are really less complicated than they seem, and we'll all have a good laugh when we awaken. 

Thank you for correct analysis.  In the meantime starter relay has been renewed (same issue but without buzz), alternator removed (shaft is free and engine can be rotated by the center bolt with a tool). Good 80Ah battery with 14V was connected directly to starter motor (even direct ground and 3 starters tested) and ONLY when also spark plugs are removed and engine is in a certain position, starter is able to turn the engine. In some other position or with sparks inserted, it can not even start turning (maybe slightly turns some mm.s).         Opening engine side covers (left=top and right=bottom) no visible deformation can be detected.       I am afraid of disasembling further (cluth centering issue on reassembly etc) but I agree that some extra mechanic friction issue should be detected.
Even if I note that, with gearbox dismounted (and complete rear drive of course), oil/water pump and alternator off, sparks out, I can rotate with some effort engine by one hand, through clutch plate (and I can check also that sprag clutch engages and spins free as it should).

With your direct battery test, if you connect earth to the starter motor body, instead of the frame, it might then crank normally and even start.

OK your battery is good for 12.8 Volts, but the plates in the battery might be all clagged up, with the result that only a small amount of Amps can get pumped through. You need to get it load tested to be sure.

daveyson wrote:With your direct battery test, if you connect earth to the starter motor body,  instead of the frame, it might then crank normally and even start.

OK your battery is good for 12.8 Volts, but the plates in the battery might be all clagged up, with the result that only a small amount of Amps can get pumped through. You need to get it load tested to be sure.

Tested already direct wiring, (including ground) from battery to starter motor. With no load spins like a wonder but fails when inserted (or cranks only without sparks ecc..)

Battery used normaly cranks a 2.0 lt diesel (both battery and car have less than 2 years). Battery is around 80 Amps.....even if I lose 70 % of it, still remains enough for the K75.
:-(

I may try to remove battery from the car and use shorter cables.