BMW K bikes (Bricks)

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1Back to top Go down    What's draining my battery? on Mon Nov 20, 2017 8:25 pm

kevinryu

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I put a new battery on my bike. Everything was great for the first month. I would use the bike most days but occasionally left her for three or four days and it started strong with no issues. Then I had to leave the country for three weeks and came home to a flat battery.

Now once I charge the battery enough to start I can ride around, starting and stopping all day - one time even riding into the night and it started in the morning. But generally if I get off the bike for more than 12 hours the battery will be too flat to start the bike again. It has just enough juice (even after four days) to prime the fuel pump but will not turn over at all.

What could be draining my battery? There was heated hand grips installed on the bike when I bought it which I disconnected first thing hoping it was the issue but to no avail.

    

2Back to top Go down    Re: What's draining my battery? on Mon Nov 20, 2017 8:57 pm

RicK G

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Do you have ABS as a faulty unit can be draining the battery. I have twice experienced this with ABS1 which has the modulators near the footpegs.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

3Back to top Go down    Re: What's draining my battery? on Mon Nov 20, 2017 10:07 pm

MartinW

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Remove one of your battery leads and put a multimeter set on amps between the lead and the battery post. take a note of the current draw. If the draw is low you could have a faulty battery, and you need to test it. If it is high then pull the fuses one by one until the amp draw drops, you then have narrowed down the problem area.
Regards Martin.

    

4Back to top Go down    Re: What's draining my battery? on Mon Nov 20, 2017 11:02 pm

RicK G

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You wont find an ABS drain by pulling fuses there is a live feed as well as a switched feed of 12v power.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

5Back to top Go down    Re: What's draining my battery? on Mon Nov 20, 2017 11:46 pm

kevinryu

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I should have specified it's an '84 k-100. I'm pretty certain it doesn't have ABS. I did disconnect the rear break light sensor while it was off the road while painting some parts of the bike but obviously this shouldn't do anything as the break light isn't staying on or anything. I will find an electrical tester and follow up with your advice Martin. Thank you!

    

6Back to top Go down    Re: What's draining my battery? on Tue Nov 21, 2017 1:53 am

charlie99

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just a question
the charge - battery indicator on the instruments is lighting up at start ,and going dull - off as you move along after a while ?


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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
    

7Back to top Go down    Re: What's draining my battery? on Tue Nov 21, 2017 3:20 am

RicK G

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Leaking diodes in the alternator will drain the battery might pay to get an auto electrician to give it a test.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

8Back to top Go down    Re: What's draining my battery? on Tue Nov 21, 2017 4:23 am

charlie99

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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
    

9Back to top Go down    Re: What's draining my battery? on Tue Nov 21, 2017 5:04 am

92KK 84WW Olaf

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84 RT doesn't have the ABS.

The alternator diode is not an uncommon one and the fix is an easy one, so cheap that if its hassle going to an auto electrician and you are ok with diy it may be simpler just to swap it out.

If your charge light doesn't come on when you switch on the ignition you wont be charging the battery, a blown bulb in side the cluster can do this! This red light must come on and then go out after you rev the engine, it doesn't go out on tickover. Interestingly the K1100 I just got has an led light in here by the previous owner, but......it goes out at about 2,500rpm.

Before you go at anything check the earthing and connections are all tight, especially the battery earth to the gear box lug. Its not a great earth and can cause non charging. Been there but being aware of the potential issue found it quickly. Its now relocated to one of the starter bolts.

Worth taking the battery and running a test on it, charge it and check it with a meter, then leave it for 12-24 hours and revisit.

If you don't have a meter totest the fuses pull them all and leave the bike overnight. If that solves the problem then its one of the circuits. If it doesn't solve it then you either have dud battery or parasitic drain. Then recharge battery and this time leave it disconnected. If its still a problem battery is toast.

In the last 10 years I have probably replaced three batteries that were bought new and went faulty.


__________________________________________________
1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 58,645 now 64,500miles
    

10Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 12:33 am

kevinryu

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I may have found the issue or maybe another) and it's not looking good. The ignition button had broken off (old and brittle) when I bought the bike but still seemed fine other than sometimes when I turned the key it would just start turning over automatically. Well today when I turned the key it began trying to turn over and wouldn't stop - even when I took the key out.. I frantically removed the fuses which of course did nothing and as the wires coming off the battery began to melt managed to disconnect the battery hopefully before the starter motor burnt out. I've tried taking the switch / signal assemble apart to see if a repair is possible and it looks like the whole assembly will need to be replaced. I can imagine with so many wires needing to be soldered in place that this will be a ver pricey job to have someone attempt.

    

11Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 2:19 am

MartinW

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Hopefully somebody out there will have a spare, run an ad in the WTB section. Beside the switch sticking there is also another cause that occurs on the Bricks. If the battery level is low, the starter relay can stick caused by the points welding together. The fix is to quickly disconnect the battery earth lead. The first time it happened to me I wasn't quick enough and literally blew out the side of the battery. Lucky I had access to plenty of water, battery acid everywhere. After it happened again I managed to disconnect the earth lead, burning a couple of fingers in the process. After that I fitted a battery isolator switch into the earth lead, it resides inconspicuously behind the LH side cover. It serves a couple of purposes, it can be used as a quick battery isolation device when working on the electrics. It can also be used as a security device by removing the plastic key.

http://www.motobrick.com/index.php/topic,8995.msg70926.html#msg70926
Regards Martin.

    

12Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 5:23 am

kevinryu

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I've just read the thread on the starter relay and as I've been consistently starting on a low battery with this drain problem I'd say that's going to the issue with it continually turning over. So I suppose the tank will have to be taken right off the bike? Will I need to drain it?

Once I clean the relay I'll be back where I started looking for the drain but at least I'll be able to use the bike. Does that switch actually kill all power the bike could use? There by enabling me to not be so concerned about what is draining the battery as I can just shut it off when I park the bike?

    

13Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 5:31 am

Andrew2

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Just out of curiosity you haven't added a USB port to your bike have you?.


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1987 K100RS
    

14Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 6:44 am

kevinryu

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No USB, there is a power point added (DC12V) ((Looks like a cigarette lighter port but not to be used as one)) which was on the bike when I purchased it.

    

15Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 7:33 am

Dai

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The tank will have to come off but it shouldn't need draining as the fuel pump has a one-way valve in it. The relay box is under the rear of the tank. The 'as always' piece of advice is; if the tank's coming off, change the fuel pipes and make them a couple of inches (50mm or so) longer. Future work under the tank will then mean only moving it to one side. Very Happy

The kill switch only kills the ignition circuit. There's an awful lot of live circuits on the K even with the ignition switch off; they just don't get called into play until various relays are triggered.


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

16Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 2:30 pm

MartinW

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The isolator switch is fitted in the earth lead and therefore kills all power.
http://www.motobrick.com/index.php/topic,8995.msg70926.html#msg70926
Regards Martin.



Last edited by MartinW on Tue Nov 28, 2017 2:33 pm; edited 1 time in total (Reason for editing : added link)

    

17Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 2:59 pm

mike d


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I assume Dai was referring to the kill switch on the handlebars (we all know what ass u me means)

Mike

    

18Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 3:07 pm

MartinW

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Never assume, that's why I tried to clarify it and posted isolator switch.
Regards Martin.

    

19Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 5:50 pm

Dai

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@mike d wrote:I assume Dai was referring to the kill switch on the handlebars (we all know what ass u me means)

Mike
I was...


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

20Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 7:26 pm

kevinryu

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Didn't have to pull the tank, just lifted the end and propped it up.. replaced the relay with a $20 one I found at a local parts store and no longer turns over when off.. starting the search for the power leak or possible dud battery now!

    

21Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 7:58 pm

robmack

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What do you mean "replaced the relay with a $20 one I found at a local parts store"? Do you mean the starter relay? Did you check the specs on the relay? Does it have the mandatory snubber circuit on the coil? You know you could blow the ICU if this is missing. That's an expensive lesson.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

22Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:08 pm

kevinryu

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Numbers all matched and the guy at the parts store seemed knowledgable and said it would be cool. I haven't tried starting it yet.. what is this about a snubber?

    

23Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:10 pm

kevinryu

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How do I tell if it has a snubber? It looks exactly like the one I pulled off.. same numbers.. just a different brand name on the top..

    

24Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:24 pm

kevinryu

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the diagram and corresponding numbers are identical.. haha got me terrified to start the bike now.. battery is at full charge and ready to go...

    

25Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:26 pm

Andrew2

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Hey Kevin, do you have a name and number for it. Maybe a photo.

Cheers
Andrew


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1987 K100RS
    

26Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:30 pm

robmack

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A snubber is a circuit inside the relay that prevents voltage spikes from occurring when an energized relay drops. It consists of either a diode or a resistor across the coil legs. If it is missing from the relay, the resulting voltage spike can kill the transistors in the ICU, requiring a new ICU. Open the relay and look for the componentry.

Schematic


If you can't open it or aren't sure, then just solder a 680 Ohm 1/2W resistor across the coil or a 1N4007 diode like this:



Last edited by robmack on Tue Nov 28, 2017 8:35 pm; edited 1 time in total


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

27Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:33 pm

kevinryu

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Narva RELAY P/No 68012BL ... Not sure how to attach pictures..

    

28Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:37 pm

robmack

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Spec sheet indicates a snubber is installed. You're OK.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

29Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:41 pm

kevinryu

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30Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 8:42 pm

kevinryu

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I can't begin to tell you guys how much I appreciate this group haha

    

31Back to top Go down    Re: What's draining my battery? on Tue Nov 28, 2017 9:58 pm

Crazy Frog

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@kevinryu wrote:I can't begin to tell you guys how much I appreciate this group haha
You certainly got the best adviser for electrical problems. Rob has been a terrific + for the forum members.
The reference of the $20 relay is something that people will keep on the back of their mind.


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

32Back to top Go down    Re: What's draining my battery? on Wed Nov 29, 2017 12:07 am

Andrew2

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@kevinryu wrote:Narva RELAY P/No 68012BL ... Not sure how to attach pictures..
Nice work Kevin. I just ducked into Bursons and they have them for $22. I'll pick up a spare tomorrow. Here's another source.
https://www.ozautoelectrics.com/narva-68012bl-12v-70amp-4-pin-normal-open-relay-resistor-protected.html


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1987 K100RS
    

33Back to top Go down    Re: What's draining my battery? on Wed Nov 29, 2017 2:28 am

charlie99

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more likely a bleed (brassslivers of metal) across the main switch contact points ...not enough to turn things on
but sufficient to bleed current could be initial cause .

a few on here have explored inside the main switch , without trying to resolve issues in some cases , but observed the start of the disintegration process of metal across contact points .

whats inside





you can see that the armature part is showing wear , and I would be thinking the stator part has very close contacts , ready to collect shaved off pieces of brass ..and conducting somewhat ..



Andrew . that relay may well be rated for 70 amps , but , once you get the main starter relay open you will see that it has a dual contactor action
this is important as there is significant amount of arcing as the relay breaks contact during a start event .

I don't believe that the narva relay mentioned will do the job for very long at all .

not saying it wont work , but long term, a very suss replacement .

just hoping to help out
cheers


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

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

34Back to top Go down    Re: What's draining my battery? on Wed Nov 29, 2017 4:16 am

Andrew2

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Thanks Charlie. I thought it may be too good to be true. I've got my old one out so I'll pull it apart tomorrow and clean it up. I've had it apart when it "stuck" the first time but it appeared ok so we gave it a bit of a clean and put a spare in instead. I think they may sometimes stick when you have a low battery but don't always stay stuck so when people open them up and they appear ok they put them back in without cleaning them and just buy a new battery. The problem seems to be that without cleaning them up eventually they will just stick again regardless of whether you have a fully charged battery.
If I remember I'll take some photos of it apart.


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35Back to top Go down    Re: What's draining my battery? on Wed Nov 29, 2017 5:29 am

charlie99

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indeed ,
if you look closely at that main switch you can see deep scoring from arcing events on the centre contact

a bit of filing nd a lot of polishing cleaned up that corrosion patch

so remember filing removes the palladium contacts surface ( so go easy as palladium is the bees knees )
polishing the surface may restore a good area of the contact area to work properly

after


sorry didn't take pics of my starter relay but similar principles apply
but since cleaning up has worked well for the last 4 years and just a few starts ...grin


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

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

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