Hello all 
Its been a couple of months that i pulled a K100RT 85 from the 8 years sleep.

Headed to a -non BMW expert- engineer since there is no old K expert around in Crete Island, Greece and the BMW official Service rejected my bike as too old  

So 3 months after this is the situation:

Mechanic swapped the fuel pump with another, non genuine, looks like it works ok
Swapped the battery with a new one but only 18AH that died already and i replaced it with a AGM 30AH
Injector cleaned
Old alarm system removed by an electrician 
Tires replaced with Bridgestones BT45
Faulty GPI switch replaced with a used one from Motoworks.uk but worked only for a few hours (according my mechanic) so i m waiting for a replacement FOC (Great service by the way the guys at Motorworks)

The problem as soon as i got the bike from the mechanic was that after 10-15 min of driving bike was like cutting fuel off/on, revs 0-2000, no throttle response engine was shutting down. Starter on right after the shutdown, engine on but with the same erratic behaviour for few miles the off again, etc etc. Got it to the mechanic, and after weeks of research the problem solved after tuning (as he said) something like a bolt under the air filter? i guess the fuel mixture?

Went happy, thought everything ok but not..
Drove the bike back home nicely run, next morning tried to ride it again,.... kaput.
Starter working but no luck to start the engine until the 18AH battery Rested in Peace. 
Charged the battery, disconnected the fuel tank, checked the cabling under the tank messed a bit with the harnesses checke grounding on the frame and.. 
Engine on!!!
Actually one bunch of cables was pressed between tank and upper frame bar.
Thought that that was the problem. Next day tried to start the bike again. No luck. Knew the trick. Removed the tank a bit, not disconnected the fuel lines, messed with the cables by just sliding my fingers under the tank and bike was on again!
To shorten the story, the same story was repeating for a couple of days . After leaving the bike idle for a couple of hours i had to mess the wiring a bit to get it back on. 
Finally the battery broke circuity and could not charge (off bike) over 11V so i replaced it yesterday with a fresh Unibat 30AH / 600 CCA.
As soon as i replaced it i noticed that the clock was off with the battery connected. 
Tried to start the bike, main switch on, kill switch on, Success! half of a turn of the starter motor was enough to get the engine on! Love the plenty of CCA!
Left the bike off overnight tried this morning, engine on again succesfully!
But the problem now is why the clock goes off as soon as i turn of the main switch???
I m affraid of what this could mean in conjunction with the previous symptoms.  Is there any serious leak? 
Checked the terminals connections to the battery, the ground on the engine right over the gear lever and everything was in place. 
Please Help! 
I feel i m so close to get it working and so far the same time....
Thank you in advance!

Welcome!

The clock should stay on when the battery is connected, something amiss in wiring? I wonder has that to do with  'removing' the alarm?

On the gear position indicator personally I won't buy used parts of those or things like brake switches. They don't last and if paying someone to do them its costly to replace them.

There is a plug which connects the power to the fuel tank, if yours is early 85 and you see the tank is bolted down when you open the seat then the plug is at the front left of the tank, underneath. You have been disturbing this and if its bad it can cut out the fuel. Easy to check and can be fixed by crimping up the pins a little. If you don't lose all your electrics when this happens this may be your issue. The fact that starter etc works is possibly suggesting this. You are also finding that moving cables under the tank can help, again suggesting to look at this.

92KK 84WW Olaf wrote:Welcome!

The clock should stay on when the battery is connected, something amiss in wiring? I wonder has that to do with  'removing' the alarm?

Same thoughts on this Olaf

On the gear position indicator personally I won't buy used parts of those or things like brake switches. They don't last and if paying someone to do them its costly to replace them.

Good thing is that they will replace it with no cost. So i'm giving it another chance. Any decent tutorial on how to remove the swing arm with the bike placed on center stand? Should i give it a chance? I'm totally disappointed with the mechanic. 

There is a plug which connects the power to the fuel tank, if yours is early 85 and you see the tank is bolted down when you open the seat then the plug is at the front left of the tank, underneath. You have been disturbing this and if its bad it can cut out the fuel. Easy to check and can be fixed by crimping up the pins a little. If you don't lose all your electrics when this happens this may be your issue. The fact that starter etc works is possibly suggesting this. You are also finding that moving cables under the tank can help, again suggesting to look at this.

Thank you! I think i ve solved this. At least for the moment. But i m going to carefully inspect all the connections under the tank and clean them properly. Any suggestion on cleaners. I m hearing about deoxit but not available in my country. What i have already is the regular WD40 and some electronics contact cleaner with pure isoprop alcohol . Think they'll do the thing?

Also, do you know what kind of fuel pump the mechanic used? There are exact fit ones available for £40-50 in UK and no modifications are required. They are a common pump used in Fiat/Lancia/Seat/Alfa/Audi/VW and more

Given that you have no main dealer its important to look at things here on the forum even if you will be using a mechanic as most mechanics do not understand the K bikes.

If you have a chance post a photograph of the wiring under that tank and also inside the electrical box under the tank. Its possible some wires are not routed correctly.

A Clymer manual is a very good idea to have. The fact that your wing arm was off means you should not have any problems but before you take it off check out the connection from the gear position indicator unit where it connects into the loom above the battery. You will see it coming up from the housing under the battery, might be a bad connection.
With where you live its important you check your cooling fan is working ok too. Run the engine until the fan comes on but keep an eye on it. If the fan kicks in that's good. If the temperature warning light comes on but the fan doesn't then there is an issue you need to address as the fan should come on before the warning light. If no fan and no warning light that's also an issue but may be a different one.

Also looking at the posts there is a Fuel Injection Control Unit [FICU] under the seat. There is a big plug goes into this behind the left side panel. If that's not in correctly it can cause cut out. That will have been out to remove the battery so important to check it.

92KK 84WW Olaf wrote:Also, do you know what kind of fuel pump the mechanic used? There are exact fit ones available for £40-50 in UK and no modifications are required. They are a common pump used in Fiat/Lancia/Seat/Alfa/Audi/VW and more

He said he used a matching specs Suzuki Vstrom pump but improvised on fitting since it had totally different diameter. Guess he 's altered the cabling connection, correct?

If you have a chance post a photograph of the wiring under that tank and also inside the electrical box under the tank. Its possible some wires are not routed correctly. 

Will be posting detailed pics this weekend. Inside the box you mention also found a round plug with nothing attached to it. Guessed it was about ABS that my bike lacks.

 before you take it off check out the connection from the gear position indicator unit where it connects into the loom above the battery

Already checked the direction from the plug to the instrument dash. Everything works as it should. Green N light on, all gear numbers displayed on the tiny LCD on the dash. 
Stripped the pins off the plugs and directly connected but no luck. Blank LCD.
Is there any other way to check the direction from the plug to the GPI switch before removing the wingarm?

With where you live its important you check your cooling fan is working ok too

Luckily this was checked and working properly. Temps here will be reaching 38-40 celcius so its a must! Is there any warning light on my K100RT? (early 1985) It has a temp gauge located in the right fairing panel and a voltage meter on the left panel.

https://www.amazon.co.uk/Benzinpumpe-K100-K1100-Fuel-Petrol/dp/B015HFKXJU/ref=sr_1_7?s=automotive&ie=UTF8&qid=1522332581&sr=1-7&keywords=K100+fuel+pump

This is one option, its also used in some model Ducatis.

I am not sure what Suzuki pump you have but the K100 pump is not a very high pressure one. You do need to know what has been done because once the wiring is modified you don't know how to sort out any future fuel pump issue. It may well be ok but you should still find out what was done. The fact that your new pump is a different diameter means that it presented a mounting problem as it fits in a retainer and is not screwed or bolted into position. Use of an unsuitable material in the fuel tank could cause debris in the tank and obstruct the fuel filter and pump. 

However you have a few things going on at the same time and its not so easy to backtrack them one at a time.

It might sound a bit scary but the best thing for you will be to learn as much and do as much of your own maintenance as possible.

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The mess

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In your signatur line it says -87.....the design on some of the connectors tells
that it's older.

It looks like mods have been done to the circuit to the clock.

Do you have a multimeter or a test lamp?

Nope it's an early 85. Yes I do have a voltage meter

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George_Pap wrote:Nope it's an early 85.

Could be a good idea to change the signature, as it is a lot of things that is different.

Easy test....if you still have problem with the clock......turn on the ignition
and remove the clock fuse (#3 from top)......does the clock go off?

Will change it for sure!!

Well I just did what you suggested. The clock went off only by removing fuse No1 ( the top one) . Also all the instruments went off..

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Yes, I did suspect that the clock was getting power from another circuit than
the original design.

Is it Power at fuse #3......do you have hazard lights...do they function?

Yes the do function properly. Just tested. To be sure. By hazzard lights you mean all 4 turn signals together , correct?

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George_Pap wrote:By hazzard lights you mean all 4 turn signals together , correct?

Yes, but it isn't that important...your turnsignal would have strange behaviour
if that circuit wasn't powered.

I suspect that mods have been done inside the instrument housing to get power
to the clock.

But you can check the wires inside the fusebox....it could be there to,
in your picture two red/white wires can be seen...one should go to the turn
signal relay (rear left corner)...the other (for the clock) should go into the
main harness.
Check that they are just the single wires...not cutted, spliced into or tampered with.

in your picture two red/white wires can be seen...one should go to the turn
signal relay (rear left corner)...the other (for the clock) should go into the
main harness.
Check that they are just the single wires...not cutted, spliced into or tampered with.

Which picture off all Inge?

The one from the inside of the relay box.

........I did call it fusebox in reply #18

Thank you so much for the help!
So I checked these two but it's getting evening and the bike is on my backyard .
From the first inspection :

In this pic I can really see them both terminating to the 3rd fuse socket.



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This one is going to the green relay box. Not absolutely sure since not enough light to carefully inspect.
But for sure it's not leaded to the main loom



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This one clearly goes through the main loom.




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You could also check the wiring going to the connectors on the rearside of
the instrument, it's two raws of contacts...clock is the two on the top of each
raw....+ is on the RHS (sitting on the bike), disconnect the connector and
check if you have power when ignition is on.

If no power, next step would be to open the instrument...
this is what you should expect...but probably it would look different.

Really thank you so much. Gonna try this tomorrow afternoon after work and keep you posted.

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PS. I see a green double (speaker wire?) non OEM wire that runs from the
relay box to the steering head....check it's connections at both ends.

Inge K. wrote:[smiley]https://2img.net/u/4211/29/48/93/smiles/112350.gif[/smiley]


PS. I see a green double (speaker wire?) non OEM wire that runs from the
relay box to the steering head....check it's connections at both ends.

I totally removed that cable , the previous owner was trying to send a line to the dashboard for usb charger but finally aborted it.

As for the clock , thanks to your advise , I followed the red/white cable to the instrument cluster and found the problem.
I m afraid that the guy that removed the alarm short circuited something during the process and there was an overheating that melted !!! the plug . Pins 1 and 2 where stuck and had melted plastic from the plug around so I cleaned them and put it back carefully until I get a new plug to replace. Clock now is working fine



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Ooof!!! Does your GPI still work? It looks like that shorted to earth via the GPI switch. There could be some damage inside the switch.

Dai wrote:Ooof!!! Does your GPI still work? It looks like that shorted to earth via the GPI switch. There could be some damage inside the switch.

Unfortunatelly GPI never worked.
But!
Now , that you mentioning the GPI, a couple of days before swapping the battery I stripped the two plugs of my GPI under the right side panel and did lot of shorting combinations trying to find out if the green neutral indicator works and the gear numbers displaying properly on the LCD screen of the instrument cluster.
They all worked but I recall sensing heat on the stripped cables in a combination of shorting.
Guess I did the damage myself.
So is there any chance to did damage inside the instrument ?
Or just in the GPI switch?
Now I solved the clock issue next step is to solve the GPI switch.
There is one GPI switch on its way from Motor works UK so any help would be appreciated !!

Thank you!

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George_Pap wrote: Guess I did the damage myself.

I'll doubt it, as that contact pin for the GPI is normally connected to ground
when the bike is parked (and in use).....it's grounded in neutral and the
three first gears.

I would guess that you have a (intermittent) short inside the instrument.
The fact that the clock did get power from a different circuit points in the
direction that things isn't as it should be inside the cluster.

Remove fuse 3 and measure the current draw, the clock pulls 0,85 mA.

Hmmm... The GPi was totally disconnected / stripped when I was playing with the cable combinations to get it to display something on the dashboard. I did it rather uncarefully touching cable with cable in all possible combinations ( the four cables of the plug leading to the instrument )
I m sure I felt in my fingers excessive heat (burning) in a combination ( maybe at that time all 4 touching each other )

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All 4 wires is connected to ground in different combination depending on
which gear that is selected.......if you connect all four together you should
get neutral and 0 in the display.

I rather think that the yellow/white wire (next to the clock power) is shorted
inside the instrument and now is a (intermittent) live wire.....this is the
reason to the heat you did feel in your fingers....and the melted plastic.
This and the fact that you have connection between switched and unswitched
power inside the instrument.

I guess someone have done some modification inside the cluster.