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Discussion Starter #1
-Rode the scooter two or three days ago, now it will not crank, nor does the headlight come on.
When the key is turned to on, I can hear the fuel pump. When the start button is pushed, I can hear a slight click.
Checked the fuses under the passenger seat, checked each one with a meter. All well there.
The radio works, dash lights are working normal.
Checked the battery 12.5v, while pushing the start button, only a slight drop. Put the charger on it anyway.
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Now the fuel tank is off, the front faring and nose or headlight is off so that I could get to relays and check the connectors. All the connector look good and the relays,?
I checked out the ground Circuit but it seems to be OK.

Found that there is no power to the headlight, low or high beam. The one ground lead to the headlights is good.

The starter relay has a red lead with 12.6 V all the time. A Black wire with 11.8V till the starter button is pushed then it goes up to 12.5. I think the back-feed on the black lead may be the alarm but I am not sure of that?
This Scooter is a 2002 with 82k.

How do you get to the starter?? I put a jumper lead on a screw driver and dug the screw driver into the starter to ground it. Nothing changed.

Does any one have any idea or guess as to what is going on?

Ideas, Ideas, Please help with any ideas......Steve
 

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I would start by removing the batt connectors, clean them and tight them good. It could be one of them is loose.
Dominique
 

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Prolly not a darn thang to do with it, butt I'd check the reverser knob anyway - just so I'd know it isn't that thang!!!
 

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Dick said:
Prolly not a darn thang to do with it, butt I'd check the reverser knob anyway - just so I'd know it isn't that thang!!!

NO KIDDING!!!! I just spend an HOUR the other day with a voltmeter and a test light trying to figure why EVERYTHING electrical worked on an LT that I installed a tranny in, and yet it did NOTHING when I hit the starter. I swear, I went and took a nap out of frustration and as I lay there I thought, "reverser switch".... I came out to the garage, flipped that switch back and forth and "Varoom"! I could not believe it!!!! I was both MAD and HAPPY at the same time. :histerica
 

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Discussion Starter #5
When I did a search of the forum I saw that and checked for that. I can hear a click when I the starter button and when I put in reverse the click does not happen.
Does any one have a wiring diagram they could share?

Thanks All Steve
 

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2005 K1200LT
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The red on the starter relay is the feed from the battery. The black from the starter realy is the feed to the starter (it actually goes to a tie point behind the battery and then a wire goes from there up to the starter). When the black wire goes to 12.5 from 11.8 still sounds like you are not getting a good ground on the starter. Try sticking a large screwdriver into the main body of the starter and pry that against the tranny. Should be able to slide one in from the right side. The only way to get to the starter is to drop and remove the transmission.
 

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Discussion Starter #7
I have tried a screw driver to ground the starter. I tried it again repeating all my trouble shooting and while pushing the starter button everything came alive. That was while I had grounded the hot lead at the starter.

I am beginning to belive the starter motor is open and the Load Shed relay is open??
NO, I don't know where the load shed relay is of if this bike has one. Wish I had a wiring diagram.


Thankyou Steve
 

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I agree it looks like a high resistance between the starter relay and the negative side of the battery. The reason there is 11.8V on the black wire is because the actuation coil of the load relief relay uses the starter as it's ground path. The connection is made at the output side of the starter relay, the same location as the black wire you are measuring. The starter resistance, probably around 15 mOhms (0.015 Ohms), is ultimately the mechanism that turns off the headlights and other high load stuff when the starter button is pressed. If there was a good ground path back to the battery there should only be a very small voltage measured at the black wire unless the starter button is pressed. When the high starting current flows through the starter the voltage at that point should rise to several volts (V=IxR). The battery voltage will also drop due to it's internal resistance. This is probably around 9V in normal operation. The load relief relay coil will now not have enough voltage drop across it to keep the relay closed so as long as high current is flowing all the loads tied to the relay are turned off.

The fact that the voltage on the black wire rises to 12.6V when the starter button is pressed indicates that the starter relay seems to be working. If you want to be adventurous you can try grounding the black wire on the starter relay to see if the lights come on. WARNING, DO NOT PRESS THE STARTER BUTTON IF YOU TRY THIS. If you do you will let all the smoke out of the jumper wire :p. If the lights come on then this is just more support for the theory that a high resistance is present in the starter circuit.

There are only a few candidates I can think of that could be causing a problem like this.

- The starter relay terminal connection.
- The 6mm black wire from there to the terminal behind the battery where a 10mm
black/yellow wire from the reverser control module ties in.
- The terminal connections.
- The 10mm black wire from the terminal to the starter.
- The chassis connection and wire to the negative side of the battery. This is likely
to another terminal connection where many ground returns come back to the
battery.
- The starter itself and it's structural mounting connection back to chassis ground.

The battery terminal connection is probably not an issue because other relays seem to be working. If there were a high resistance at either battery terminal then nothing would be working.

The curious thing is that there is any voltage change at the black wire. This would indicate that the path back through the starter is not a complete open circuit. I calculate that the resistance would be around 4000 Ohms. This is based on the assumption that the load relief relay coil is about 250 Ohms and there is the measured drop of 0.8 V at the output of the starter relay. That means 0.8 V divided by 250 Ohms results in about 3 mA (0.003 Amps) (I=V/R) flowing through the relay coil and subsequently the whole starter circuit. 12.6V divided by 0.003 Amps results in 4200 Ohms (R=V/I) in the overall circuit and 250 ohms of that is due to the relay coil.

When the starter relay closes the resistance back to the positive side of the battery is very small. The voltage at the output of the starter relay then rises to close to what the battery voltage is.
 

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Discussion Starter #9 (Edited)
No Cranking -now really baffeled

After hearing what Jim said I went out and did a voltage drop test on the starter body to battery cradle, reading was 0.0 as should be.
Did it from the battery + to the starter terminal, reading was 0.428v. Pushed the start button and it fell to 0.001v. Battery is a little low due to messing with it all day, 12.08v.
Did a voltage test of the + lead of the starter to the + terminal of the battery - readings
11.8v, push start button 12.02v.
Ground the start motor + terminal and the lights come back on.

I don't know what to do now but to go after changing the starter motor.
Jim: What would you do next? I'm crying here. I found where the start motor is.
Thanks all,

Steve
 

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Discussion Starter #10 (Edited)
Had a brain storm at 1am. got up and disconnected the starter lead ( About time, huh.) at the block by the battery. I think this is a main fuse? If it is, it checked good.
Checked ohms of the starter motor. Got 5.71K ohms.
Checked at the motor and at the frame with the same reading. I now believe the motor is good and the lead is good. Now I am deflated again. Now what????
Thank you all for letting me rant. I will ruin my rep tomorrow by going to work in a cage.

Steve
 

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2011 R1200RT
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Steve, at this point I would take the battery out of the bike and give it a full charge. It can't hurt since you have been playing and testing, which weakened the battery. This could help prevent false readings.
I am still baffled by the fact that your headlight does not come on. Is it stock or did you switch to HID. If you switched, did you install a relay?
 

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There is no fuse in the starter circuit. The screw terminal behind the battery is just a terminal block to bring together two different sources of power that can drive the starter motor. One source is the starter relay and the other is the Reverser Control Module.

My resistance calculation was to indicate what you should be seeing from your problem not what the resistance should be on a working system. A resistance of 5.7k Ohms is not good. The total resistance from the starter relay back to the negative side of the battery should be very low, probably less than 0.25 Ohms. If you are reading 5.7k Ohms from the starter input lead you disconnected from the terminal block to the starter case then the problem is either the input lead, the connection at the starter input stud or the starter.

If you can see the input stud on the starter and can get the ohm meter on it, measure the resistance from the stud to the case. If it is 5.7k Ohms then it looks like the starter is bad. A typical automotive starter resistance is in the neighborhood of 0.06 Ohms. A motorcycle starter could have more resistance because they are lighter duty, 700 Watts in the LT. This means the starter is pulling around 55-75 amps and the starter resistance must be in the 0.13 to 0.23 Ohm range depending on what voltage the 700W is rated at. I used 12.6V and 9.6V to come up with that range of values.
 

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Discussion Starter #13
I have been in denial. I don't want it to be a starter motor. But, I am convinced Jim is right.
To prove it I connected a battery jumper cable to the lead from the starter and applied power. Nothing. Removed the spark plugs, placed in 2nd gear and jogged the engine by moving the rear wheel. Applied power to the starter again and it turned for two seconds and dragged or turned slowly before stopping again. Does anybody have starter motor brushes??
.thank you all for the help and special thanks to Jim for his time and explanations so that even I could understand.
I guess with 82k on the scooter, while the trans is out might as well do some PM such as:
Clutch, rear main oil seal, Slave cylinder. Please let me know if there is anything else that should be done while Scooter is torn apart. Have I heard anybody say Tech session? haha.

Thanks again..............Steve
 

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Discussion Starter #14
Final diagnosis:
There was some gear oil in the starter motor which had fouled up the brushes and the commutator.
So if a Scooter has no lights and won't crank, The grounding brush in the starter motor may will be the cause. It was with mine. I found one other post with this problem but it didn't get going, I tried to PM the guy but it came back Undeliverable.
Hope this helps someone when their trying to troubleshoot a problem like this.

STeve
 

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Steve: thanks for posting the final result! That is a good find - I, myself, would not have know about connection between the lights-off and no-start symptoms.
 

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k2steve said:
Final diagnosis:
There was some gear oil in the starter motor which had fouled up the brushes and the commutator.
So if a Scooter has no lights and won't crank, The grounding brush in the starter motor may will be the cause. It was with mine. I found one other post with this problem but it didn't get going, I tried to PM the guy but it came back Undeliverable.
Hope this helps someone when their trying to troubleshoot a problem like this.

STeve
So Steve, is the Starter OK now? Where did the oil come from? Inquiring minds want to know!

Hope you did manage to get it working correctly.

John
 

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Discussion Starter #17
The starter projects into the transmission and the motor. It is double ended.
The oil seal on the transmission end leaked and this is the same end the brushes are in.
Finally the ground brush would not make-up and that is what caused the trouble....Steve
 

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Dick said:
Prolly not a darn thang to do with it, butt I'd check the reverser knob anyway - just so I'd know it isn't that thang!!!
Another one is the kill switch on the right handle bar.
 
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