Thanks to Daveyson my original electrical problem is resolved (I had swapped positive battery lead with starter lead). Now starter won’t crank, neutral light and gear indicator won’t work. Could I have fried something?

OK1987LT wrote:Thanks to Daveyson my original electrical problem is resolved (I had swapped positive battery lead with starter lead). Now starter won’t crank, neutral light and gear indicator won’t work. Could I have fried something?

I am not following what you mean "swapped positive battery lead with starter lead".  

Where were they connected?

Point-Seven-five wrote:

OK1987LT wrote:Thanks to Daveyson my original electrical problem is resolved (I had swapped positive battery lead with starter lead). Now starter won’t crank, neutral light and gear indicator won’t work. Could I have fried something?

I am not following what you mean "swapped positive battery lead with starter lead".  

Where were they connected?

I installed incorrectly. Starter lead on positive battery terminal, positive battery lead on starter terminal.

OK1987LT wrote: Could I have fried something?

You could have blown something, like a fuse, perhaps. Check the fuse panel.

Okay, please pardon my ignorance, but where were the other ends of these leads connected.

Point-Seven-five wrote:Okay, please pardon my ignorance, but where were the other ends of these leads connected.

Just as an observer not as an experienced remote viewer—even after having listened to Art Bell for hours on the night shift while rolling spiral ductwork pipe—my opinion is the other ends were connected where they always had been.

Laitch wrote:

OK1987LT wrote: Could I have fried something?

You could have blown something, like a fuse, perhaps. Check the fuse panel.

Checked #1 fuse. Fuse good. Swapped with #2, same 7.5 amp. Good. Voltage at fuse #1 12.4v. I’ll check the others tomorrow.

Does your brick start if you pull in the clutch?

I guess the other cluster lights are on when you say the neutral light and gear indicator are off.

So, in other words, the battery positive and starter cables were backwards on the start relay?  Is that right?

If the other usual lights aren't on, it could be a simple problem, like hopefully just the kill switch in the off position.

For safety reasons, the starting circuit doesn't allow the engine to turn unless your brick is in neutral, which is varied (edit: varified) if the neutral light is on. Pulling the clutch bypasses that.

If still no go, which lights are on at the instrument cluster?

daveyson wrote:Does your brick start if you pull in the clutch?

I guess the other cluster lights are on when you say the neutral light and gear indicator are off.

No. Clutch no crank. Yes other cluster lights on.

daveyson wrote:If the other usual lights aren't on, it could be a simple problem, like hopefully just the kill switch in the off position.

For safety reasons, the starting circuit doesn't allow the engine to turn unless your brick is in neutral, which is varied if the neutral light is on. Pulling the clutch bypasses that.

If still no go, which lights are on at the instrument cluster?

Other lights on. Kill switch works, when used lights go out.

With the ignition on and start button pressed you should have about 12Volts at the starter motor terminal, whatcha got?

Here's how to get the air filter and air box out to access the fuel pressure regulator.

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/k75pa.rehab/k75parehab.htm#fuelair


If you think it's flooded you can pull the spark plugs and use a hair dryer/heat gun to evaporate the fuel in the cylinders. That's worked for me in the past.

I use paint thinner and steel wool to clean out old gas tanks.

daveyson wrote:With the ignition on and start button pressed you should have about 12Volts at the starter motor terminal, whatcha got?

No voltage. 710 ohms resistance.

Is your battery fully charged? 

There is a cable from the battery to the start relay.  The terminal on the start relay that cable is connected to should always be at 12Volts relative to the negative terminal on the battery.  Is it? 

The other cable connected to the start relay goes to the starter motor.  If you check the resistance from that terminal on the start relay to the terminal on the starter motor the reading should be almost 0.0 ohms.  Is it?

Measure the resistance between the body of the starter motor near the mounting screws and the negative terminal on the battery.  It should be very close to 0.0 ohms.  Is it?

If the above checks confirm that the cables are correctly connected and you have a fully charged battery then bypassing the start relay contacts with a large metal object like a wrench should make the starter turn the engine.  Does it?

These checks will confirm whether or not the problem is in the power wiring to the start relay and the starter motor.  If they show good, you can move on the tracing the signal that energizes the coil of the start relay and the start relay coil.

Point-Seven-five wrote:Measure the resistance between the body of the starter motor near the mounting screws and the negative terminal on the battery.  It should be very close to 0.0 ohms.  Is it?

This doesn't tell you a whole lot, if anything. The amount of current that an ohmmeter puts through a circuit to measure resistance is negligible. Even if a cable is degraded with many strands broken then it can still read a closed circuit (0 ohms) with a multimeter but not be able to deliver the necessary amperage to the starter.

With ignition on, which instrument cluster lights are on, which meter backlights are on (all four, or two top, or two bottom) and is the clock and it's backlight on? Do the indicator warning lights on the instrument cluster work?

With the start button pressed, does the headlight cut out?

It seems to me like power isn't getting from fuse 1 to the starter button, or it's getting power but not sending it.

daveyson wrote:With ignition on, which instrument cluster lights are on, which meter backlights are on (all four, or two top, or two bottom) and is the clock and it's backlight on? Do the indicator warning lights on the instrument cluster work?

With the start button pressed, does the headlight cut out?

It seems to me like power isn't getting from fuse 1 to the starter button, or it's getting power but not sending it.

I’ll check power to start sw tomorrow.

Point-Seven-five wrote:Is your battery fully charged? 

There is a cable from the battery to the start relay.  The terminal on the start relay that cable is connected to should always be at 12Volts relative to the negative terminal on the battery.  Is it? 

The other cable connected to the start relay goes to the starter motor.  If you check the resistance from that terminal on the start relay to the terminal on the starter motor the reading should be almost 0.0 ohms.  Is it?

Measure the resistance between the body of the starter motor near the mounting screws and the negative terminal on the battery.  It should be very close to 0.0 ohms.  Is it?

If the above checks confirm that the cables are correctly connected and you have a fully charged battery then bypassing the start relay contacts with a large metal object like a wrench should make the starter turn the engine.  Does it?

These checks will confirm whether or not the problem is in the power wiring to the start relay and the starter motor.  If they show good, you can move on the tracing the signal that energizes the coil of the start relay and the start relay coil.

Thanks. Good info. I’ll check tomorrow.

If the headlight cuts out with the start button pressed, that would be a quick way to verify that the start button is getting power and also sending it to the starter and load shed relay.

Another quick check, with a red battery jumper lead clamped to battery positive and with the other end a quick contact to the starter terminal, if the starter turns then the battery and earth are good, and the problem is a lack of power, which is a safe bet since you're reading 0 Volts at the starter terminal.

OK1987LT wrote:

Point-Seven-five wrote:Is your battery fully charged? 

There is a cable from the battery to the start relay.  The terminal on the start relay that cable is connected to should always be at 12Volts relative to the negative terminal on the battery.  Is it? 

The other cable connected to the start relay goes to the starter motor.  If you check the resistance from that terminal on the start relay to the terminal on the starter motor the reading should be almost 0.0 ohms.  Is it?

Measure the resistance between the body of the starter motor near the mounting screws and the negative terminal on the battery.  It should be very close to 0.0 ohms.  Is it?

If the above checks confirm that the cables are correctly connected and you have a fully charged battery then bypassing the start relay contacts with a large metal object like a wrench should make the starter turn the engine.  Does it?

These checks will confirm whether or not the problem is in the power wiring to the start relay and the starter motor.  If they show good, you can move on the tracing the signal that energizes the coil of the start relay and the start relay coil.

Thanks. Good info. I’ll check tomorrow.

Battery 12.6v
Start relay voltage 12.6v
Starter to ground is correct
Jumping terminals at start relay will spin the starter

daveyson wrote:If the headlight cuts out with the start button pressed, that would be a quick way to verify that the start button is getting power and also sending it to the starter and load shed relay.

Another quick check, with a red battery jumper lead clamped to battery positive and with the other end a quick contact to the starter terminal, if the starter turns then the battery and earth are good, and the problem is a lack of power, which is a safe bet since you're reading 0 Volts at the starter terminal.

Headlight does not go out when start button pressed. Voltage at starter switch is 11v battery is 12.6v.

Okay, your power wiring to the starter is good. 

There is a connector on the side of the start relay.  It has a brown and black/yellow wires connected to it.  Pull it off and check the wiring.

First, is there continuity from the contact with the brown wire to the negative terminal on the battery?  This is the start relay coil ground.

Second, is there 12v on the contact with the black yellow wires when the key is on and you press the start button?  This is the power that energizes the starter relay coil.

With the connector off, check the resistance between the two connections on the starter relay.  I don't know exactly what you should read, but if it is an open circuit or very close to 0.0 the coil is probably bad.  I am guessing you should read something like a couple hundred ohms.

Point-Seven-five wrote:Okay, your power wiring to the starter is good. 

There is a connector on the side of the start relay.  It has a brown and black/yellow wires connected to it.  Pull it off and check the wiring.

First, is there continuity from the contact with the brown wire to the negative terminal on the battery?  This is the start relay coil ground.

Second, is there 12v on the contact with the black yellow wires when the key is on and you press the start button?  This is the power that energizes the starter relay coil.

With the connector off, check the resistance between the two connections on the starter relay.  I don't know exactly what you should read, but if it is an open circuit or very close to 0.0 the coil is probably bad.  I am guessing you should read something like a couple hundred ohms.

I think you have identified the problem. Brown wire contact to neg bat terminal is open. FYI resistance on relay field 49 ohms. Next I’ll run a jumper from relay to neg terminal. Thanks for the help.

OK1987LT wrote:

Point-Seven-five wrote:Okay, your power wiring to the starter is good. 

There is a connector on the side of the start relay.  It has a brown and black/yellow wires connected to it.  Pull it off and check the wiring.

First, is there continuity from the contact with the brown wire to the negative terminal on the battery?  This is the start relay coil ground.

Second, is there 12v on the contact with the black yellow wires when the key is on and you press the start button?  This is the power that energizes the starter relay coil.

With the connector off, check the resistance between the two connections on the starter relay.  I don't know exactly what you should read, but if it is an open circuit or very close to 0.0 the coil is probably bad.  I am guessing you should read something like a couple hundred ohms.

I think you have identified the problem. Brown wire contact to neg bat terminal is open. FYI resistance on relay field 49 ohms. Next I’ll run a jumper from relay to neg terminal. Thanks for the help.

More troubleshooting. Wire from start relay to ICU has continuity. Could problem be the ICU? Could I just wire direct from start relay to neg terminal/ground point on frame?

Sure, adding a temporary ground wire from the start relay coil is a good way to test the start button and the wiring for the 12v side of the coil.  

It is beginning to look like the problem may be in the ignition control unit or the ground wiring for it.

Point-Seven-five wrote:Sure, adding a temporary ground wire from the start relay coil is a good way to test the start button and the wiring for the 12v side of the coil.  

It is beginning to look like the problem may be in the ignition control unit or the ground wiring for it.

Ground wire from ICU to frame is good. ICU bad?  Any way to do a functional check on ICU or just replace it?

It's getting earth but not sending it to the starter relay, that's a test fail. You might be lucky, give the connections a scrub and spray of deoxit, that might fix it. If you post a photo of the starter relay that might reveal something.

daveyson wrote:It's getting earth but not sending it to the starter relay, that's a test fail. You might be lucky, give the connections a scrub and spray of deoxit, that might fix it. If you post a photo of the starter relay that might reveal something.

I have replaced the starter relay already.

OK1987LT wrote:Any way to do a functional check on ICU or just replace it?

There is a series of tests of the ICU in the Troubleshooting the EFI document found in the Tech Page in its Electrical section. Scroll down through the document. The pin numbers and array of the pins in the unit's plug are shown along with the test.

Point-Seven-five wrote:Sure, adding a temporary ground wire from the start relay coil is a good way to test the start button and the wiring for the 12v side of the coil.  

It is beginning to look like the problem may be in the ignition control unit or the ground wiring for it.

ICU wire harness disconnected. With jumper from neg terminal to ground on start relay AND jumper from pos terminal to the other start relay connection, starter will spin.

Just to confirm that the wiring from the start button to the relay coil is good, run a test ground wire from the start relay coil and try the start button.  The starter should spin.  then you can be absolutely sure that the problem is only in the Ignition Control Unit.

Daveyson's advice to clean and reconnect the big plug on the ICU is excellent and the next thing I would suggest.

Point-Seven-five wrote:Just to confirm that the wiring from the start button to the relay coil is good, run a test ground wire from the start relay coil and try the start button.  The starter should spin.  then you can be absolutely sure that the problem is only in the Ignition Control Unit.

Daveyson's advice to clean and reconnect the big plug on the ICU is excellent and the next thing I would suggest.

Should I leave the jumper from neg term to start relay connected?

I wouldn't.  That wire is just temporary to confirm that the coil is good and getting the signal from the start button.  If there is a problem in the ICU, it needs to be fixed.

Point-Seven-five wrote:I wouldn't.  That wire is just temporary to confirm that the coil is good and getting the signal from the start button.  If there is a problem in the ICU, it needs to be fixed.

Ok. I’ll chk tomorrow.

OK1987LT wrote:

Point-Seven-five wrote:I wouldn't.  That wire is just temporary to confirm that the coil is good and getting the signal from the start button.  If there is a problem in the ICU, it needs to be fixed.

Ok. I’ll chk tomorrow.

Couldn’t wait. I removed temp wire from neg term. Chkd start relay ground to start sw. nothing.

You've lost me.  When the temporary Start Relay ground wire is connected to ground does the Start Button make the starter run?

What we are trying to do is bypass the ground through the ICU.  The rest of the start relay wiring should be intact so you can use the Start Button to run the starter.

Point-Seven-five wrote:You've lost me.  When the temporary Start Relay ground wire is connected to ground does the Start Button make the starter run? 

What we are trying to do is bypass the ground through the ICU.  The rest of the start relay wiring should be intact so you can use the Start Button to run the starter.

Temporary Start Relay jumper is removed. All wiring is back to nominal. Jumped from Start Relay ground to Start sw. Nothing. No starter

The temporary ground wire is supposed to go from the ground terminal on the starter relay to GROUND not the starter switch or wherever you were connecting it.  You are using it to go around the ICU.

Obviously, my ability to communicate is not working this evening.

On the side of the start relay there is a push on connector.  It has two contacts in it that connect to spades on the side of the relay.

The two two spade contacts connect to the relay coil.  The connector that goes on the spades has wires with two different color markings.  The wires with the black/yellow are from the start button and send 12 volts to energize the relay coil.

The brown/red wire is the start relay coil ground connection that goes to ground through the ICU.  Right now I think we have a problem in the ICU.  We are trying to confirm that problem.

What you are trying to do is connect a wire that goes directly to ground.  The negative terminal on the battery is a good place to connect it.  

You can make the connection at the relay connector by sticking the stripped end of this temporary ground wire into the start relay connector that has the brown/red wire on it, and then pushing the connector onto the spades on the relay coil.  

Try to be careful and avoid any of the bare wire strands of the temporary wire from touching the other spade.

Once you have made these connections, turn on the ignition and try the start button.  If I have successfully communicated these instructions, I would expect that the starter will work.  That would indicate that indeed the ICU is preventing the start relay coil from being grounded.

If the starter does not work, it means that there is another problem somewhere and that one of the earlier tests was misleading.

Point-Seven-five wrote:On the side of the start relay there is a push on connector.  It has two contacts in it that connect to spades on the side of the relay.

The two two spade contacts connect to the relay coil.  The connector that goes on the spades has wires with two different color markings.  The wires with the black/yellow are from the start button and send 12 volts to energize the relay coil.

The brown/red wire is the start relay coil ground connection that goes to ground through the ICU.  Right now I think we have a problem in the ICU.  We are trying to confirm that problem.

What you are trying to do is connect a wire that goes directly to ground.  The negative terminal on the battery is a good place to connect it.  

You can make the connection at the relay connector by sticking the stripped end of this temporary ground wire into the start relay connector that has the brown/red wire on it, and then pushing the connector onto the spades on the relay coil.  

Try to be careful and avoid any of the bare wire strands of the temporary wire from touching the other spade.

Once you have made these connections, turn on the ignition and try the start button.  If I have successfully communicated these instructions, I would expect that the starter will work.  That would indicate that indeed the ICU is preventing the start relay coil from being grounded.

If the starter does not work, it means that there is another problem somewhere and that one of the earlier tests was misleading.

I have not been communicating well either. My temporary jumper wire from start relay ground WAS to the negative terminal. Starter does not spin. I have ordered a new (NOS) ICU unit from EBAY. Once installed I will update. Thanks for all the help.

Point-Seven-five wrote:Once you have made these connections, turn on the ignition and try the start button.. . . I would expect that the starter will work . That would indicate that indeed the ICU is preventing the start relay coil from being grounded. If the starter does not work, it means that there is another problem somewhere and that one of the earlier tests was misleading.

OK1987LT wrote:Starter does not spin. I have ordered a new (NOS) ICU unit from EBAY.

It's going to be a grand reveal when the replacement ICU is installed!    I'm just wondering if 12V were verified at the yellow/black connection of the starter relay when the starter button was pushed. To tell the truth, in all the excitement I've kind of lost track myself.

Laitch, now that you mention it, there never was confirmation of the 12 volts at the Black/Yellow wires.  This thread is getting pretty long and I'm am not the best anymore at following these long discussions.   I think that advancing senility is getting rampant in my brain now.

Point-Seven-five wrote: I think that advancing senility is getting rampant in my brain now.

Unlikely. I think somebody on here is amusing themselves with homemade chatbots, and having a larf.

Laitch wrote:

Point-Seven-five wrote:Once you have made these connections, turn on the ignition and try the start button.. . . I would expect that the starter will work . That would indicate that indeed the ICU is preventing the start relay coil from being grounded. If the starter does not work, it means that there is another problem somewhere and that one of the earlier tests was misleading.

OK1987LT wrote:Starter does not spin. I have ordered a new (NOS) ICU unit from EBAY.

It's going to be a grand reveal when the replacement ICU is installed!    I'm just wondering if 12V were verified at the yellow/black connection of the starter relay when the starter button was pushed. To tell the truth, in all the excitement I've kind of lost track myself.

Voltage at yellow/black connection 0.8v.

With Start button pushed?

I'm confused, I thought it cranked with an earth jumper wire, then in a later thread, it doesn't.

Wondering if the pins for 85 and 86 are original.

OK1987LT wrote:Voltage at yellow/black connection 0.8v.

Admittedly, I'm a slave to manufacturers' instructions. I accept that sometimes they can be fallible but my experience is that they are slightly less fallible than people in general, the paradox being that people compose the instructions.  Then I must contend with my interpretation of them, all of which could lead to a loop of despair similar to the one described in RickG's signature. Nevertheless, I tend to rely on them anyway.

With that in mind, and in accordance with the attached diagram and the starting sequence description from BMW below it, 12V should be delivered to pin 10 with the ignition switch turned to On and the kill switch lever in its central position. That is before the starter button is even pushed and that is how the ICU gets operating power. Under those conditions, did you ever get a reading of 12v at the socket of pin #10 in the ICU plug?

I realize that you're likely fed up with all this right now and I actually hope that you're doing something enjoyable—if filtering through all the incoming comments, remarks and advice is not a source of enjoyment already—while the replacement ICU is winging its way toward you, so I won't hold my breath for any reason other than practice for free diving while snorkeling.

I hate to adit it but my concentration level on this thread is waning.