BMW K bikes (Bricks)


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jr

jr
Silver member
Silver member
Images of the INSIDE of a Starter Relay off a 1988 K100LT Starter%20Relay%20insidesImages of the INSIDE of a Starter Relay off a 1988 K100LT Starter%20Relay_Front_BackImages of the INSIDE of a Starter Relay off a 1988 K100LT Starter%20relay%20notes

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jr

jr
Silver member
Silver member
I have a question. In A1 and 4 you'll notice 1 of the contact points appears to be much smaller (or worn) and does not make contact when the relay is activated. Is this supposed to be this way or should it make contact? Would this keep the bike from starting? Currently my bike will not start.

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RT

RT
Life time member
Life time member
Hi jr
have you seen the price of copper lately, we should all just scrap our relays and flog them off, I didn't realise they were so complicated.
welcome aboard from Oz.
RT

    

charlie99

charlie99
VIP
VIP
it looks to me as if the left hand contacts have been arcing as power is applied through them ,which i would concider to be normal but it also looks as though the armature is bridged so that the other contacts also should take some of the load . but they look as clean as ..
i did notice that the there is a slight diference between them in as much as the left armature contact side is bent( a typical sign that there has been some welding of the burned contacts ) and it looks as though the second set of contacs dosent meet or is high resistance . it would be a good idea to straighten the bent one ,,,so they both line up , there could be some gunk on the face of the clean looking contacts so i suggest cleaning both faces of the bits that touch together (with maybe a blunt points file .dont use emery paper as it may leave granules of the abrasive in the metal or worse score the metal too much ......or even just some cardboard to polish the surfaces )

these contacts are usually coated with paladium ( a rarer but stronger metal which wont weld together as easy as if it was just brass) so look after the surfaces .

in the end you are looking for a verry low ohms contact between both sides of "the points"
so get out your trusty multimeter (a requirement with all machinery where electrics are involved) put it to low ohms 0 - 200 energise the relay (without the battery being connected to the feed) and measure both sides . it should be the same as touching the probes of the test leads together, something like 0.01 to 0.10 or some cheaper meteres 0.1 - 0.2 ohms

if not ,you have found a contributing factor to the starter not turning ......but i suggest that the problem is possibly the brushes in the starter

    

Crazy Frog

Crazy Frog
admin
admin
I agree with Charlie99. The first thing to check should be the starter.
One quick and dirty way to ensure that the starter is in good shape is to push the starter button and monitor the head light. It should goes off as soon as you touch the button.


__________________________________________________
Images of the INSIDE of a Starter Relay off a 1988 K100LT Frog15Images of the INSIDE of a Starter Relay off a 1988 K100LT Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

jr

jr
Silver member
Silver member
Wow-thanks guys. and yes. maybe we should sell the copper!

So Charlie - I bent the left armature. When it came out of the bike both armatures were perfectly straight but as you noticed the left one was worn and did NOT make contact when the other one did. Another user recommended that I could possibly bend it down and gently file it so they would both make contact - a possible temporary solution.
Multimeter - I have one and I am dying to learn how to use it.
I set it to 20M. when I touch the top and the bottom of the tip of the armature (either) where those "buttons" are I get a 0.0 reading on both just as if I were touch the red and black leads together.
And yes - if by bridged you mean connected you are correct.
I'll attach another photo.
Images of the INSIDE of a Starter Relay off a 1988 K100LT Starter%20Relay%20Top

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jr

jr
Silver member
Silver member
Points! the Buttons are points. Ok, I get it now.
I was very upset when the bike broke down but with this site I'm now almost glad it did..... well not really but it is fun to learn and work on it.

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jr

jr
Silver member
Silver member
Images of the INSIDE of a Starter Relay off a 1988 K100LT Starter%20relay%204A

http://www.jrdelia.com
    

Avenger GT

Avenger GT
Life time member
Life time member
"I set it to 20M. when I touch the top and the bottom of the tip of the armature (either) where those "buttons" are I get a 0.0 reading on both just as if I were touch the red and black leads together."

Setting your multimeter to 20M for checking continuity across points is no good. the 20M range will measure up to 20 Mega-Ohms, which is a very high resistance (20 million Ohms to be precise) . If the points were slightly burned they might have a resistance of several Ohms - lets say 100 for example. A meter set at 20M could see 100 Ohms as a short circuit, that is zero Ohms. You need to set the meter to the lowest resistance range, typically 200 Ohms to get an accurate reading of the resistance across the points. Ideally you want zero Ohms, or as close to it as possible- the higher the resistance here, the less current that can flow through to the starter, and the greater the voltage drop across the relay, which just heats up and burns out some more!

    

jr

jr
Silver member
Silver member
Oh My God, that makes so much sense. I love you!

OK - so I just set it to 200 and rechecked. I get .2 on both points, from both sides - burned side and otherwise.
I might try to gently file it, blow it clean with air, and then bend as precisely as possible as a temp fix just to see if the bike will start.
I plan to replace it as soon as I can in any case.

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jr

jr
Silver member
Silver member
One more MultiMeter Question.

What setting do I use to check the voltage on my battery. I thought I had it right but I at most get a reading of about 11V but when I bring it to a real garage they check it on a much better macine end every time get a reading between 12.75V - 12.85V. Is it me or my MultiMeter (MM)?

Ex. My battery has been on a 12V tender for 2 days now (in my home). I just checked it on the 20 setting and got 10.65V but I'll bet money that if I bring it to the corner tire/battery place it will read 12.85V.

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charlie99

charlie99
VIP
VIP
jr ...you need to measure the large lugs ....where the battery comes in and where the starter takes off from this relay this is the path the high current electricity flows .....

secondly whilst activated ....if you can , check for airgap between the unburned looking contacts

a good way of checking this is to put a roll your own cigarete paper between the contacts then activate the relay ,,,,if you can pull the cigarette paper out easily or it doesnt hold ...there is airgap (btw a cigarete paper is meant to be 1/1000 " or one "thou" as its called or there abouts )
you know its good, if the paper is hard to pull out .....you can also tell if the contacts have a weld mark (pointy piece of metal) on them still ...if the paper rips

most manafacturers make allowance for high energy contacts ...the one with the narrower width to the tip is more or less sacrificial to the one with the larger width, i think its suposed to take the high electrical arc on release of the relay whilst the magnetic field is collapsing


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

charlie99

charlie99
VIP
VIP
jr wrote:One more MultiMeter Question.

What setting do I use to check the voltage on my battery. I thought I had it right but I at most get a reading of about 11V but when I bring it to a real garage they check it on a much better macine end every time get a reading between 12.75V - 12.85V. Is it me or my MultiMeter (MM)?

Ex. My battery has been on a 12V tender for 2 days now (in my home). I just checked it on the 20 setting and got 10.65V but I'll bet money that if I bring it to the corner tire/battery place it will read 12.85V.

1> the multimeter could be out of calibration jr
2> the internal multmeter battery could be flat also i have seen strange things when this happens ...usually they read low as you say yours is .......its to do with the electronics inside the chip not doing a good analogue to digital conversion sample or what ever
3> the internal fuse (in the multi meter) may have been affected when measuring some time ago ....wortha look

maybe you should look for "k bike"s excellent tutorial on explanations ,,all things multimeter ish ... he posted it quite recently

    

jr

jr
Silver member
Silver member
LOL - You beat me to it.

http://www.jrdelia.com
    

Avenger GT

Avenger GT
Life time member
Life time member
Quickest way to check the meter is to try it on a known good battery and see what voltage show up on it.

    

jr

jr
Silver member
Silver member
SUCCESS, even though accidentally! Bring a photographer batteries are something I DO have!
I tested many. I got 1.25V on new AAs. 2.5V on a 3V lithium.
Out of frustration I puled the 9V from the MM and for good measure also checked the fuse. The fuse was fine but re-seating it must have corrected something.
The Bike battery now reads 12.5V and all the AA and camera batteries are reading as expected now.

YEAH for minor victories! That was cool!

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Avenger GT

Avenger GT
Life time member
Life time member
If the test equipment is not OK then nothing is OK. You can end up chasing your tail around a problem and getting nowhere fast! The trick when fault finding is never to assume anything, and check everything. Years ago I got caught out by a dud fuse in a Grundig TV set. The picture was cramped up from the bottom of the screen, the fuse in the power feed to the frame circuit looked OK, but the voltage at the frame chip was very slightly low. After changing the chip and several other components, genius here decided to measure the voltage at the other side of the fuse. Thats right - the voltage was correct. The fuse had gone resistive, about one Ohm, but enough to upset the chip. Turned out to be a bad batch of fuses, because I had several more afterwards.

    

charlie99

charlie99
VIP
VIP
doncha hate that avenger ?????


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

jr

jr
Silver member
Silver member
The Original Starter relay that I tried to fix did not work. The headlight did dim when I hit the starter button and I did hear a hiss for a few seconds when I let off the starter button so I assume the fuel pump is working so..... I'm guessing I really do need a new starter relay and battery.

Today I ordered a new battery ($124) & new starter relay($47). Not the exact Starter relay but I was assured it would work.

Relay part Number: 0 332 002 150

MotoBatt QuadFlex MBTX30U SLA Battery

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K-BIKE

avatar
Life time member
Life time member
As has been commented elsewhere you definitely have an issue with the wiring because the headlight should go out when the starter is run because the load shed relay is there to do just that. When the starter motor stops running the load shed relay pulls back in and restores the headlight and all supplementary power not related to starting the engine.
Regards,
K-BIKE

    

charlie99

charlie99
VIP
VIP
the ground connection to the load shed relay is fed through the starter motor

the relay itself draws verry little power so will not turn the starter ...but if this is not working one could assume the starter is also not working ...reminder to replace ...check the brushes in the starter


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

Crazy Frog

Crazy Frog
admin
admin
Again, I am posting my favorite schematic.

In order to have a relay working, you have to feed the coil with a positive and a negative. In the case of the load shed relay, when the starter is turning, the coil is fed with 2 positives and it's the equivalent of not sending any voltage. If the coil of the load shed relay is not energized, nothing will pass through the contacts and lights, horn and flashers are disabled.
Here ya go....

Images of the INSIDE of a Starter Relay off a 1988 K100LT Starter


__________________________________________________
Images of the INSIDE of a Starter Relay off a 1988 K100LT Frog15Images of the INSIDE of a Starter Relay off a 1988 K100LT Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

jr

jr
Silver member
Silver member
To be clear -the headlight does go out when I try to start the bike - I just couldn't see it too well in the sun from where I was standing.
Waiting on a new starter relay and battery now.

http://www.jrdelia.com
    

jr

jr
Silver member
Silver member
1 more thing. I never thought to mention it but when I got my bike out of winter storage there was a bit of strong arming involved and my light switch has been stuck on HIGH BEAM ever since. I never thought it a problem because it just feels like the switch itself is in need of repair and I never thought it was an electrical issue.
Could I be wrong?

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