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1Back to top Go down    Electrical gremlin on Tue Nov 06, 2018 9:12 pm

Bikesmith

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Hey friends,
My usually dead reliable 1985 K100RS is giving me trouble in the middle of a touring trip and I'm hoping you guys can help me out.
Here's what happened: About 300 miles into my day I was pulling into a small town. As I slowed down coming into town I noticed that my starter was coming on intermittently. I'm not sure if it started right then, or if it had been doing it a while and it was only when I showed down that I noticed. I pulled into a parking lot to check it out.
When I tried to start the bike again, the dashboard lights came on normally. Pushing the starter button activated the fuel pump but I got nothing from the starter. Bad starter relay seemed like a good guess, so I replaced that and the load shed relay too, just in case, congratulating myself for carrying spares. But it had no effect. Starter button still activated the fuel pump, but not the starter. I did confirm the starter relay is clicking. That was the end of my power of diagnosis. Isn't it amazing how much harder it is to think clearly with a broken bike by the side of the road than comfortably in your home shop?
I figured I might have killed my starter, so I tried bump starting the bike. It worked! Yay! Sunset was approaching fast and I was starting to think it might be an overly interesting evening. By the way, bump starting was way easier than I expected.
So I continued my ride thinking I'd killed my starter. But then I noticed that my headlight was out and none of my switchgear was working properly. No horn. Pushing either turn signal button or the cancel button makes all four turn signals and the dash light flash once. Other than that the bike rode perfectly.
During the rest of my ride to tonight's hotel, I started wondering if one of the switchgear connections to the loom might have come loose. When I got here I checked that. Nope, they're both tight. Wiggling them made no difference.
So, any thoughts about what might be going on? I'm hoping you guys might have an idea that can get this trip back on track. If not, I'm bump starting and heading for home as quickly as possible tomorrow morning. I have a pretty good selection of tools to try ideas, but no multimeter (Damn! That's a mistake I won't make again).
What do you think?
- Jon


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

2Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 9:34 pm

charlie99

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check the fuses ,
could it be that one if those torpedo switches (brakes , clutch , etc ) has busted, blowinga fuse
or chafed wire somewhere ?

just a thing worth checking

good luck



Last edited by charlie99 on Tue Nov 06, 2018 9:35 pm; edited 1 time in total


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

3Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 9:35 pm

duck

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Starter motor getting dirty inside can cause all sorts of gremlins. That would be my first guess.


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

4Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 9:43 pm

Bikesmith

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Charlie, I checked the fuses. They're all good.
Duck, good thought on a dirty starter as something to check out when I get home, but I think pulling the starter might be a bit ambitious for a hotel parking lot repair.
- Jon


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

5Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 9:48 pm

RicK G

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Remove the lead from the relay to the starter at the relay and see if that makes the headlight come on. If that works as I suspect it will then remove the 2 pin plug onto the starter relay and reconnect the main lead and see if that makes the headlight come on as I suspect it will.
Try that and see how it goes.
I will be on line for quite a few hours yet so if you need any more help I will be here.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

6Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 10:14 pm

Bikesmith

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Rick,
No change. I tried disconnecting the lead to the starter (#87), tried disconnecting the 2-pin plug, and just for the heck of it, tried disconnecting #30 too. No headlight with any setting.
- Jon


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

7Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 11:50 pm

Point-Seven-five

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I am pretty sure your ignition switch is whacked. That is why the headlight and handle bar switch functions don't work while the engine runs perfectly. Just last weekend I repaired the ignition switch on a K75 with those light problems. A poor connection in the ignition switch on the lighting contact combined with a weak battery could produce what you are experiencing. The ignition switch on these bikes is really a piece of crap.

You mention the starter running when the engine was running. That is a symptom of welded contacts probably caused by starting with a weak battery. The weak battery is also why after you replaced the relay you were hearing the start relay click when you pushed the start button.

It's also possible, but I suspect unlikely that you have bad grounds or funky battery connections. Wouldn't hurt to check them.

You might also want to get the battery load tested. I am pretty sure they will do a load test for you at any battery shop or some auto parts places like AutoZone.



Last edited by Point-Seven-five on Tue Nov 06, 2018 11:57 pm; edited 2 times in total


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

8Back to top Go down    Re: Electrical gremlin on Tue Nov 06, 2018 11:52 pm

RicK G

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@Point-Seven-five wrote:I am pretty sure your ignition switch is whacked. That is why the headlight and handle bar switch functions don't work while the engine runs perfectly. Just last weekend I repaired the ignition switch on a K75 with those light problems. A poor connection in the ignition switch on the lighting contact combined with a weak battery could produce what you are experiencing. The ignition switch on these bikes is really a piece of crap.

You mention the starter running when the engine was running. That is a symptom of welded contacts probably caused by starting with a weak battery. The weak battery is also why after you replaced the relay you were hearing the start relay click when you pushed the start button.

It's also possible, but I suspect unlikely that you have bad grounds or funky battery connections. Wouldn't hurt to check them.
Yep that is the likely culprit


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

9Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 12:55 am

Laitch

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@Bikesmith wrote:Duck, good thought on a dirty starter as something to check out when I get home, but I think pulling the starter might be a bit ambitious for a hotel parking lot repair.
You needn't wait until home. Try #1 on this list. If that helps, clean the starter after cleaning the ignition switch and replacing the battery when you arrive home. Laughing


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1995 K75T 68,000 miles
    

10Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 1:25 am

Bikesmith

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Rick and .75, I tried rebuilding the ignition switch. I concede it wasn't the best possible job doing it in a hotel room with no deoxit or even a pencil eraser, but I tried. No difference. Still no headlight.
The battery, though... That triggered a thought. Something I didn't mention in the original story is that it was a pretty cold day of riding. So I had the heated grips and my heated vest on most of the day. My battery is actually pretty old. I'm now wondering if that high load was the final straw. There's an Autozone right next door to my hotel. I think I'll take the battery over to check it in the morning.
Latch, I'll try that starter cleaning tip in the morning, too.
Thanks, guys!


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

11Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 5:46 am

duck

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It might make for a temporary fix but whacking the starter motor with a crescent wrench or something to knock the dirt around might help.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

12Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 6:32 am

92KK 84WW Olaf

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An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now 83,050 miles
    

13Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 8:50 am

Crazy Frog

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Definitively a starter problem.
When the starter is not energized, it provide ground to the electric system.
Having the starter running permanently for a while certainly chewed the brushes.


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1986 k75, 1985 K100rt, 1985 K100rt/EML sidecar.
    

14Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 9:07 am

duck

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@92KK 84WW Olaf wrote:An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.

You can get the starter motor out without messing with the coils.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

15Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 9:22 am

92KK 84WW Olaf

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@duck wrote:
@92KK 84WW Olaf wrote:An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.

You can get the starter motor out without messing with the coils.

You can.......just found it easier to unbolt them but not disconnect them.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now 83,050 miles
    

16Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 9:38 am

duck

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Just remove the two bolts that hold the back of the starter down. Then rock it side to side while pulling.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

17Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 10:47 am

kioolt

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@Crazy Frog wrote:Definitively a starter problem.
When the starter is not energized, it provide ground to the electric system.
Having the starter running permanently for a while certainly chewed the brushes.

Just so that this doesn't become the truth because it was on the internet I would like to clarify something. The starter does not provide ground for the electric system as stated above. It only provides the ground for the load shed relay.


__________________________________________________
2004 R1150RT 186,800 miles
1991 K100LT 128,700 miles
1982 R100RT 106,900 miles
Total422,400 BMW miles

AMA,BMWRA,BMWMOA


The cheapest thing on a BMW is the nut that connects the handlebars to the seat.
    

18Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 11:11 am

Crazy Frog

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@kioolt wrote:
Just so that this doesn't become the truth because it was on the internet I would like to clarify something. The starter does not provide ground for the electric system as stated above. It only provides the ground for the load shed relay.

This is correct and this is shown on my diagram (Not from the internet but from my EFI troubleshooting page). if the coil of the load shed relay is not activated or doesn't get enough power, lights, flashers, horn,.... will act weird or not work at all.
This is why when reading the symptoms of the problem, I pointed out the starter.

I also forget to mention something about bum starting a K100.
Even if the starter doesn't work, it's a very good idea to press the starter button when releasing the clutch.
Why and what's happening when you press the starter switch?

The starter relay and Fuel Injection relay close, Hall sensors get power.
The FI relay energizes (+) the fuel pump, the idle switch, the injectors and the air flow meter.
The Jetronic receives (pin #4) the signal that the engine is starting and it sets itself on starting mode (enriching the air/fuel mixture)
Electronic ignition module pin # 9-10-14 send power to the ignition coil
Electronic ignition module pin #8 send engine rpm info to pin #1 of FI computer
Electronic ignition module pin #7 send ground to the coil of the FI relay as soon as the starter switch is depressed. The ground will stay on after the starter switch is released as long as the Electronic ignition module receives a signal from the Hall sensors.
Notes:
Under 1300rpm, the timing is set to 6 ̊. Then, the Electronic ignition module will modify the timing according to the engine RPM.[/quote]


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1986 k75, 1985 K100rt, 1985 K100rt/EML sidecar.
    

19Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 9:48 pm

Bikesmith

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Hey everybody,
I made it home! I came home the direct way instead of the meandering route that I took yesterday. About 300 miles. The bike ran perfectly except for lack of starter, lights, horn and signals.
Starting the bike cold this morning in sub-freezing weather was challenging. Took me about 10 attempts, but I got it. After that it was a pretty uneventful ride. I stopped at gas stations that had a bit of a slope as you left, and the bike bump-started perfectly every time.
I gave a lot of thought to what might be wrong and I kept coming back to the load shed relay. The problems were isolated to load-shed items and everything else worked perfectly. But I tried replacing the relay yesterday and it didn't help. Crazy Frog's suggestion about fried starter failing to provide ground to the relay makes perfect sense. It explains everything.
So, is the starter completely shot or can it be repaired? Crazy Frog, you specifically said that the brushes were fried. I see they're available as a brush set (Not even expensive cheers ). Is that likely to set things right or have I done other damage to the starter, too?
Thanks again for your help, guys!
-Jon


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

20Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 10:03 pm

Crazy Frog

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Most of the time, a starter could be fix.
The first thing to do is to dismantle it to assess the damages.
Caution: Mark the position of the front and back cover. If you reverse them, the starter will turn the wrong way.
What you will mostly find is that the brushes are gone and the copper track on the shaft may dirty or scored. It's easy to sand it to be smooth again.
Open the starter, take pictures and we will help you in your assessment.


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1986 k75, 1985 K100rt, 1985 K100rt/EML sidecar.
    

21Back to top Go down    Re: Electrical gremlin on Wed Nov 07, 2018 10:08 pm

kioolt

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Here's something that a lot of people get confused. The load shed relay will not keep the starter from working. The starter will keep the load shed relay from working.

A very easy way to tell if the starter is keeping your load shed relay from working (no headlight is a symptom) is to just jump the starter terminal to ground with the key on. DO NOT PUSH THE START BUTTON, BAD THINGS WILL HAPPEN IF YOU PUSH THE START BUTTON WITH THE JUMPER ON. If the headlight comes on that means you have completed the missing ground path through your starter with your jumper wire and energized the load shed relay.


__________________________________________________
2004 R1150RT 186,800 miles
1991 K100LT 128,700 miles
1982 R100RT 106,900 miles
Total422,400 BMW miles

AMA,BMWRA,BMWMOA


The cheapest thing on a BMW is the nut that connects the handlebars to the seat.
    

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