My k75s won't start after sitting

[MC Dig]

Hi,

I have a 1987 k75s with about 45k miles.  It was running great when I left this past July for vacation.  I left it parked at the airport; I was late for my plane so I did not have time to disconnect the battery. So when I got back the battery was dead as I expected.  I took it to get it charged, put it back and it won't start.  The head light will come on, the tailight comes on.  The turns signals do not work, the gear indicator is not on.  when I go to start it, nothing happens, I don't hear the fuel pump come on or anything.  I checked the fuses under the left side panel and they are all good.  I have no idea what it could be, maybe a loose connection somewhere?   Has anyone else had this problem?

Thanks for any help.

[Croak]

Lead/acid batteries don't like deep discharge and can be ruined by it. Probably what has happened, it has lost most of it's surface area of the electrodes due to sulphation (correct word?). It can get up to 12V when charged, but as soon as any real current is needed, it chokes.

[MC Dig]

I bought the battery from Advance Battery Systems (where I bought it)  they specialize in batteries I was going to take it there to get checked and charged but they were closed over the weekend.  So I took it to Autozone instead and they put it on their trickle charger over night.  They said it never got past 62% capacity and that it needed replacement.  So I brought it in to the battery place and they charged it all day and said it was fine.  I put it in the bike and got nothing like I said.  My friend was there with his car and just to check I hooked up his battery to mine with jumper cables, and nothing changed - though he did not start the car up - but that shouldn't matter I don't think.  So, it could be still the battery, but then it should have worked hooked up to my friends car, right?  Maybe I should take the battery back and get it double checked. 

[MC Dig]

The other thing is that, when I hit the start button, I get nothing.  It does not even try to turn over - in addition the turn signals don't work.  So maybe there is a connector loose or something. Is there anything that would cause the turn signals, horn or gear indicator to not work and the bike to not start?  Like I said the headlight comes on fine and also the tail light works fine.  Again I checked all the fuses under the left side cover. 

Again thanks in advance for any help or suggestions. 

[frankenduck]

Take the battery to an auto parts store and ask them to "load test" it.

If you trickle charge a battery that's been damaged by a deep discharge that won't fix it.

[argent brick]

Lead/acid batteries don't like deep discharge and can be ruined by it. Probably what has happened, it has lost most of it's surface area of the electrodes due to sulphation (correct word?). It can get up to 12V when charged, but as soon as any real current is needed, it chokes.

This is what happened on my K75. Had a normal lead/acid battery. Replaced it with an AGM. Very happy so far.

[2000rsv]

I put it in the bike and got nothing like I said.  My friend was there with his car and just to check I hooked up his battery to mine with jumper cables, and nothing changed - though he did not start the car up - but that shouldn't matter I don't think. 

Just an FYI - If you are jumping with a car, do not start the car.  The current put out by the car's charging circuit can do damage to the bike's system.

J

[frankenduck]

I put it in the bike and got nothing like I said.  My friend was there with his car and just to check I hooked up his battery to mine with jumper cables, and nothing changed - though he did not start the car up - but that shouldn't matter I don't think. 

Just an FYI - If you are jumping with a car, do not start the car.  The current put out by the car's charging circuit can do damage to the bike's system.

J

This is hogwash.  Alternators do not generate current.  They generate voltage potential.  The difference in voltage potential is what causes current to flow. That's how electricity works.  The wattage rating for an alternator is merely a maximum measure of how much electrical power the alternator can supply at it's regulated voltage. It does not mean that its always putting out that much power.  It only puts out as much as is needed by the difference in voltage potential across the devices in the circuit.

The voltage potential of an alternator is limited by the voltage regulator.  Unless the voltage regulator on the car allows a higher voltage than the vehicle being charged electrical system can handle then no damage will occur.

[Scott_]

The other thing is that, when I hit the start button, I get nothing.  It does not even try to turn over - in addition the turn signals don't work.  So maybe there is a connector loose or something. Is there anything that would cause the turn signals, horn or gear indicator to not work and the bike to not start?  Like I said the headlight comes on fine and also the tail light works fine.  Again I checked all the fuses under the left side cover. 

Again thanks in advance for any help or suggestions.

A couple of things come to my mind.
did you miss connecting any of the wires when reconnecting the battery?

Have you tried cycling the kill switch a few times? (you probably have, but have to ask anyway)

[Motorandy123]

Well the gear indicator will stop the bike from starting. You have to have neutral to power the starter.
The little switch down under the swing arm controls that indicator but it could be in and around the dash
too. Did it rain while you were gone and soak into the dash?

[frankenduck]

You have to have neutral to power the starter.

Or pull in the clutch.

[Motorandy123]

If you look here on page 4 there is a diagram with everything involved in starting;

http://smithduck.home.comcast.net/~smithduck/bmw/tech/K100%20troubleshooting%20Starting.pdf

There is a fuse going to the flashers (and horn) but it should still start with that bad. Sorry I had just read about
fooling the bike when the dash is replaced and that article said the bike wouldn't run without the gear indicator
calling out neutral. It turns out there is a diode OR to allow starting with the clutch pulled in OR in neutral.

[frankenduck]

It turns out there is a diode OR to allow starting with the clutch pulled in OR in neutral.'

It's much simpler than that.  There are two wires that can provide power to the starter button: one from the clutch swtich and the other from the gear position indicator circuit in the cluster.

[MC Dig]

Thanks for all the suggestions. 

The reason I don't think it is the battery is that I hooked it up to my friends car battery and still got no response.  Nothing happens, it does not make any noise or even try to turn over.  It was parked at lax in a covered garage, so nothing got wet (i am pretty sure we did not have any rain here in LA anyway). 

So, I guess I will pull the battery and take it back to the shop and double check it - but I don't think that is the problem.  It is odd that the turn signals and horn don't work, I checked all the fuses. 

Also I pulled the clutch in when I tried to start it.  So again if anyone has any other ideas, I would greatly appreciate hearing them. 

Thanks

[frankenduck]

Does the headlight go out when you hit the starter button?  (It should.)

It's possible there is corrosion in the starter/kill switch

[MC Dig]

That is a good question, I actually thought about that but did not check it.  I am going back to the airport (where the bike is parked) tonight and I'll check that. 

[mac]

Just an FYI - If you are jumping with a car, do not start the car.  The current put out by the car's charging circuit can do damage to the bike's system.

This is hogwash.  Alternators do not generate current.  They generate voltage potential.  The difference in voltage potential is what causes current to flow. That's how electricity works.  The wattage rating for an alternator is merely a maximum measure of how much electrical power the alternator can supply at it's regulated voltage. It does not mean that its always putting out that much power.  It only puts out as much as is needed by the difference in voltage potential across the devices in the circuit.

The voltage potential of an alternator is limited by the voltage regulator.  Unless the voltage regulator on the car allows a higher voltage than the vehicle being charged electrical system can handle then no damage will occur.

Well put, duck! Right as ever.

[K75RT Keith]

If I have this right, the lights don't light, horn doesn't beep, pump doesn't run and the starter doesn't turn.  Not to be a smart ass but, check the kill switch.  It should be pointed straight up.  Might want to flip it back and forth a few times.   Start with the battery leads and clean those connections first (on both ends).  Then pull the right side switch and clean with contact cleaner. recheck and/or replace the fuses.   Try putting it in 2nd and rolling it back or forward to move cylinders and then try starting it.  Mine as a spot on the starter that needs cleaning and it will do something similar to what you've mentioned. 

[MC Dig]

Ok, I just went to check out the bike.  I toggled the starter switch back and forth and still nothing.  I hit the starter button and the headlight does not dim.  the horn, turn signals and brake lights do not work.  Though the headlight and tail light do work.  I hooked up my jumper cables from my truck and that did not change anything, so it is not the battery. 

So, there is a spot on the starter switch that needs cleaning or the starter itself?  I took apart the starter this spring and cleaned it out, so that should be good.  It is interesting that it was running and starting fine before I parked it. 

Ok, any other suggestions would be greatly appreciated. 

[frankenduck]

The load shedding relay should dim the headlight so it sounds like you're not getting power from the starter button.  That and it not starting.

First place to start is to see if you're getting power TO the starter button.

Remove the right combo switch.  Phillips screw near the the turn and cancel buttons.  Use a good screwdriver and pressure as those threads can be sticky and it's easy to strip the head if you aren't careful.

There are two metal tangs on the back of the start/kill switch assembly.  (The starter button makes contact with both of them to send power to the starter relay.)  One of those should be at 12V when either the clutch is pulled in or the N indicator is lit.

I'll PM you my phone # so you can call me when you're at the bike and don't have to run home to post and then run back out to the bike.

[MC Dig]

Ok, I got the bike towed to my house so it is easier to work on.  I tested the switch and there is no voltage when the clutch is pulled in.  I also tested each of the blade fuses behind the left side cover for continuity and they are ok. 

Also the digital clock stays on after I switch the ignition to off and remove the key. 

Ok,  any further help would be appreciated.

[Inge K.]

If you ain`t got power at the starter switch when the clutch is pulled (or in neutral) check if you got power at fuse #1.

If you ain`t got that, kill switch is the next to check.

It`s normal that the clock stays on, when the key is removed.

Inge K.

[MC Dig]

Ok thanks,

The only fuse with power is the second from the top.  All the others have no power that is with the key in the on position and the bike in neutral. 

The kill switch is right there with the starter switch, right?  There are two contacts on that assembly and I tested those and there is no power.

[Inge K.]

The second fuse is for park/tail, then it is the ignition switch that is the problem.
Have you turned the ig.sw. to the second position, or does stop at the first position?

Inge K.

[MC Dig]

Inge K.  You are a brilliant genius!!!!!

So, I have 3 keys for the bike.  The original one with the black tilting head, the original silver key and a third spare I had made.  When I left for my trip I lost my keys somewhere at the airport after parking the bike - I was using the original silver key.  When I got back I was trying to use the spare, which I guess I never fully tested because it would not go past the first position.  I did not notice and just assumed something was messed up after it sitting for so long. 

So, after your last post I went up and found my original black key and it starts right up!!!!

Thanks so much for your insightful, intelligent and thoughtful trouble shooting !!!

I could have spent a couple of weeks f ing around testing different stuff trying to get it to work.  Ha ha.

Ok, thanks again and to everyone else who offered their help.  Also the bike is for sale here in Los Angeles 42k miles, clutch spline and the drive shaft splines have all been lubed up, new ebc  brake pads and a batttery that is only 6 months old.   and it is in decent shape.  It has a salvage title because it got knocked over in a parking lost this past spring.  It rides great and I am letting it go for only $1700.