BMW K bikes (Bricks)

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KJustin

KJustin
Silver member
Silver member
I've been doing cosmetic work, converting my 85 K100RT to a cafe racer. Bike was running fine. I took off the tank and my homemade seat/tail for painting. While I had things apart I did some minor electrical cleanup. E.g. Put a disconnect plug on for tail light and rear turn signals and put an aluminum cover over the battery, moved the horn.

I had the battery on the charger, so it's topped up. Took it off for a few days. Turned the key, headlight and speedo lights came on like they should. Hit the starter button and everything went dead. Bike never turned over, no fuel pump noise. Nothing. Silence. No power anywhere except for the clock on my acewell speedo. Flipped the key a few times and got zero power anywhere, except, as noted the clock is keeping time and never cut out.

After pulling each fuse--all looked good--I took my aluminum battery cover off. Turned the key, lights came on, hit the starter and same total failure (except clock) as described above.

Then I jiggled the battery around a little. Turned the key, lights, starter, fired right up. Repeated 3 times.

I have a lithium ion battery--if it makes a difference.

Could this just be a loose or corroded battery connection that I revived by jiggling things about? Or is there something potentially more sinister I should address?


    

RT

RT
Life time member
Life time member
Sounds like a problem I was having, turned out to be a bad earth connection. Check the battery earth to gearbox area, undo it and give it a good clean, then the earth under the tank, has a few wires joined on. Mine turned out to be a loose battery terminal post, after I'd done all the above, of course. Look for easy problem first and good luck.


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2011 R1200RT
    

KJustin

KJustin
Silver member
Silver member
Thanks RT Today. A few months back I chased a starting gremlin that turned out to be a loose plug to the ICU at the headstock. Of course it was the last thing I checked. As a result, all the chasing led me to clean every connector under the tank including the main earth with deoxit.

I wouldn't be surprised if you are right about the battery to engine earth. I know that's a known problem and I did have the battery wires off when I was moving my battery about. I'll clean and torque the connections to be safe.

Any other takers on things I should check/consider?


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1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

robmack

robmack
Life time member
Life time member
Possibly the ignition switch is flakey and needs disassembly/cleaning.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

brickrider

brickrider
Life time member
Life time member
As has been noted often here on this forum, DeOxIt is your friend when dealing with such puzzles.

    

Holister

Holister
Life time member
Life time member
The LiFePO battery could be the culprit. Their chemistry is a bit different and require some consideration when starting, during warmup and also when charging. Stress like poor charging and cold weather can affect their initial cranking amps. They need to push a little current first to get going.

You said you had the bat on charge.
What charger are you using?
How long was it charging?
Which lithium battery do you have?

LiFePO4 batteries have a very low 'self dissipation rate' and don't really require additional charging unless really necessary and they're easy to overcharge. They don't like desulphination mode as they don't sulphate. also they may not trigger the float mode on a trickle charger which can remain in full charging mode till you disconnect it. That will damage a litjium battery
When stressed they can take a little time to get going/reactivate.

Sounds like there was maybe enough amps to activate the LSR solenoid coil but not enough initially to power the fuel pump and starter till it recovered.

Unlike a lead acid bat, which must be maintained above 75% charge, LiFePO4 bats can be discharged MUCH further without damage so not really necessary to keep it topped up which can damage the bat if not properly done.

Just my thoughts


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1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Complete electrical failure--odd experience but working now; would still like input Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
+1 on RBM's comment about the ignition switch.  Your symptoms sound an awful lot like what I was experiencing this spring with my bike.  That switch is a very bad design.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

KJustin

KJustin
Silver member
Silver member
I'll need to check the ignition switch. It was replaced when I bought the bike in 1999, because the original had gone bad. I rode the bike quite a bit when I first got it (all sorts of weather, lots of rain) and then didn't ride it for about 8 years due to a combination of my father being killed in a MC accident and having little kids myself. Point being, the switch has light use, but still could have corrosion, so I'll check it.

The battery is a Scorpion SSTX-300FP. It has a button on the top to test the charge which illuminates three LED lights, or only 1 or 2 if it's not at full charge. The bike had been sitting 2.5 months so I pressed the button and only got 1 LED light. So I put a trickle charger (1 amp, I think) on for 24 hours. After that I had 3 LEDs and took the charger off. Then I let it sit for a 3-4 days. Then hit the starter and the rest of the story is above. Also, temperatures have been warm here. It was probably 95F in my garage when I tried to start the bike.

I wasn't aware of the issues noted by .75 WRT Lithium iron batteries (except that I did know the need to be warmed before cranking in cold weather) but I think I was pretty conservative in my approach to charging. Does it sound likely that I did damage?


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

Holister

Holister
Life time member
Life time member
I just put the battery issue up as another possibility. The other suggestions are also valid and should be investigated, but I have to point out that everything was seemingly working till the starter button was pressed and then the lights went out. Sounds like the LSR was doing its job but no juice getting to other components whether that was due to a poor connection or no juice from the battery??? Something doesn't seem right. Could be a combination of a couple of things maybe. Often faults don't surface till something else fails or falls below performance levels like battery voltages. Always pays to keep all connections and switches clean and functioning rather than wait till something happens imo and then its a struggle to diagnose.

Battery damaged??? Who knows? The Scorpion has a Battery Management System built-in. What will tell is the service life you get out of it. But what I understand is that you should be able to let that battery sit for months disconnected (some say even a year) without charging and it should fire the bike up no probs. It's certainly got enough CCAs. One thing's for certain, they don't like trickle charging, but with the correct charger, IF you have to use one, they should charge up very quickly. Depends on the charger and the size of the battery but anything from 30 mins to 2 or 3 hours.... but in theory you shouldn't have to.

In case you're wondering, I don't use a LiFePo. I considered it but went for a quality AGM. Similar performance but a trade-off between less $$ and the weight.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Complete electrical failure--odd experience but working now; would still like input Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

KJustin

KJustin
Silver member
Silver member
Thanks all. Turns out the earth to the gearbox was loose. Must have gotten better contact when I moved the battery around to get it started. Anyway, I tightened it up and starting is flawless as before. But, I'm still going to do a quick clean of the ignition switch to be safe.


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Glad you found the problem Justin.  I have worked as a sailboat mechanic now for nearly 15 years.   Experience has taught me that the first thing to check when there are general electrical system problems is the condition of the main system grounds.  If they aren't clean and tight all sorts of strange, non-specific things will happen.  I hope you will remember this experience.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

KJustin

KJustin
Silver member
Silver member
Yes, agreed.  Looking back, I realize that I even guessed it in the original post.  Probably should have checked the ground before posting.  However, I always learn more by involving the good folks on the forum and greatly appreciate the assistance.  Thanks all!


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1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

RT

RT
Life time member
Life time member
And the winner was.......RT
Glad you got it sorted mate it is so frustrating.


__________________________________________________
2011 R1200RT
    

indian036

indian036
Life time member
Life time member
@RT wrote:And the winner was.......RT
Glad you got it sorted mate it is so frustrating.
The voice of wisdom and experience.  Smile

Bill


__________________________________________________
1985 K100RT  VIN 0028991  My original Very Happy   (Historic rego)
1985 K100RT  VIN 0029036  BOB the Blue Old Bike  (Historic rego)
1990 K100LT  VIN 0190452  Work in progress
1984 K100RT  VIN 0023022  Work needing lots of progress

1986 K100RT  VIN 0090542  Work needing lots and lots of progress
1993 K1100LT  VIN 0183046  Work in progress
1993 K75S  VIN 0213045  Newest toy, slightly non-original
    

Holister

Holister
Life time member
Life time member
Good that it was a simple fix.
Onya RT Very Happy


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Complete electrical failure--odd experience but working now; would still like input Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

RT

RT
Life time member
Life time member
Ha, as most know I'm a jubbo with this thing but it just sounded like something that happened to me. 
My exuberant response is meant only as a self satisfying gesture, not to take anything away from the other
very legit solutions.
Made an old man happy for a minute (grandkids are here for holidays so it was just a short happy)
Cheers


__________________________________________________
2011 R1200RT
    

88

88
Life time member
Life time member
I've had that twice lately now the key is getting stick so I'm starting at the ignition switch!


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Complete electrical failure--odd experience but working now; would still like input Ir-log11 88....May contain nuts!Complete electrical failure--odd experience but working now; would still like input Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

charlie99

charlie99
VIP
VIP
good onya bob ...!!

cheers Justin ...good to hear you got a fix


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OComplete electrical failure--odd experience but working now; would still like input Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

Stan

Stan
Life time member
Life time member
Bob, for a moment I thought you said that you were a dubbo......we will have to educate our brothers from the north of the equator about that. Razz


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1983 K100 basic vin 0003960 colour red  GONE
1987 K100RT vin 0094685 colour, orange peel, sorry, pearl..GONE
F800R black
    

RT

RT
Life time member
Life time member
As soon as it warms up I will be in Dubbo Stanley.
Thread back to Justin and his success.


__________________________________________________
2011 R1200RT
    

KJustin

KJustin
Silver member
Silver member
Another interesting development.  Had some similar power failure after tightening the earth on the gearbox.  I jiggled the negative terminal on the battery and that solved the problem.  So apparently the battery is defective also (connection on the negative terminal is screwed down tight).  The battery has two sets of terminals, so I'll see if the other side is any better.  Going to be 2 weeks until I can do that since I'm going out of town shortly.


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

RT

RT
Life time member
Life time member
My problems also included an ever loosening negative connector on my battery, same symptoms happened if I hit a speed bump or driveway lip, dead in the water. I eventually put those star washers under the battery terminal screws and have had no problems since then.
It was the only time I ever felt like a guru, surrounded by youngsters (who pushed me into the carpark at Maccas), sidecovers off, ecu plug out, tray out, multi meter on, tighten tighten, back together, turn on, puff of smoke and away. "Who was that masked Mekhanic" I heard them say.


__________________________________________________
2011 R1200RT
    

charlie99

charlie99
VIP
VIP
brilliant bob !!!  wow ....would have loved to have seen that in real life

your just too cool !

besides got to set an  example to those young whippersnappers I recon ....could  be, they actually didn't (...and never will), have a clue as to what you did and why ..

cheers from up here




Justin ...just a heads up
many of us have upgraded that dreaded earthing cable to something quite a bit more substantial
along with meatier lugs that connect to the battery and gearbox earth point ....some have even taken an auxiliary earth cable ( negative )  to the under tank earthing point ....(don't forget  that brown is the euro equivalent of earth or negative )


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OComplete electrical failure--odd experience but working now; would still like input Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

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