Hi excuse me I've been distracted for a year back on it now 
Ok so Ive got bmw k75 had an accident fitted new engine case after getting   all alloy out of engine engine will and does swing round so I chopped up the loom for my cafe racer so after trying to do that I've got another complete loom it's from an abs model mines non abs but I'm sure that can be binned so it's all fitted and starter won't spin my starter button was busted  so I twisted the green and yellows together and the black black and yellow are at starter button the clutch switch I've joined them together same as pull the clutch and joined  no's 5 and 6 in the cluster plug. I've had relays checked and there all good and a new battery  I've removed the starter it's good  where am I going wrong previous to accident she's a blinder.  Also is anyone on this forum heard about top yoke collapsing under heavy braking I know it's an old bike someone turned in front of me and the yokes shattered And I crashed

Does your moto have an ignition switch that operates, Ribi?

I fitted a toggle switch years ago .so yes it does sir I use the green wire and the red I don't use the light blue ones thank you latch for your interest

Ribi wrote:I fitted a toggle switch years ago .so yes it does sir I use the green wire and the red  I don't use the light blue ones . . ..

How closely do the colors and location in the attached diagram match those of the wires you're using? This diagram for for K75 wire is one of several from Clymers manual. 

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I'm using this diagram and this matches my bike sir

Ribi wrote: so I twisted the green and yellows together and the black black and yellow are at starter button the clutch

I want to understand what you are doing, Ribi. If you start your sentences with a capital letter and end them with a period that would help separate your ideas better for me. 

In the quote above you, did you mean to write "twisted the green wire and green yellow wire together"? You also refer to a "black black" wire. Did you mean to write "black green wire and black yellow wire"? I'm trying to go by the diagram you posted.

Have you verified there is 12V in the green wire when you're trying to run the starter? Where else have you verified there is 12V during the starter trial?

Dear Mr Laitch,
From the ignition wiring I have used the green wire and the red wire to my push to start button ..
At the right handle bar control switch I have twisted the green wire and the green and yellow wires together for continuity I assume it's the kill switch..
Ii then run the black wire and the black and yellow wires each side of the press to start button..
Power is sent to the starter relay at 12.50 volts and reduses to 9.45v when button is released ...
The brown and red wire in the same plug is constant live at 4.50v

I've tried to include photos to help

Help needed too many photos

this is the same post Wiring woes

Yes it is but now I have another uncut wiring loom but I cant get the starter to engage any help is welcome and gratefully received thanks

Thread moved from Troubleshooting - General to Troubleshooting - Electrical.

With respect two wheels I'm not getting much advice from any area many thanks for moving me lets hope I can get some help

Hello is there anybody out there. Please help thank you

Click the Portal box at the top of this page, Ribi, and then click on the Tech Page link. After doing that, click on the I agree button. In the Electrical section that appears, click on the Electrical Diagrams link. That is a diagram of a K100 wiring system that is similar to your K75’s system. At the top of that diagram are boxes. Click on the Starter box. Carefully look over the wiring connections. Look at the red wire connections because those are the 12V connections from the battery. Have you connected all the correct wires to each other so only the starter will operate, or are you expecting the engine to start? 

What is your basic goal right now—getting the starter to rotate the crankshaft, or getting the engine to start? In your other thread about this problem, daveyson gave some interesting suggestions but you did not respond indicating you tried any of them. Starting the engine on your K75 requires more complex electrical connections than those in starting the Hillman Imp you mentioned in your other thread. Your photos aren't much help to me personally because you don't explain what you are doing in them or why you are doing it. Your description of the wire colors connected to the starter button—presumably the button that was destroyed in the accident—does not seem to agree with the wiring diagram you provided. 

One reason you might not be getting all the help you need here is that the wiring of your motorcycle seems to have been drastically modified by the combined processes of making it into a cafe bike and then crashing it in an accident. Those circumstances make it difficult many of us to recommend the usual methods of troubleshooting. 

The situation isn't hopeless but will likely require abundant patience, understanding, and time from you.

Thanks for your reply but what don't you understand ? The engine is ready to run I took the chopped up loom off and replaced it with a very good condition second hand for an ABS model which I am confident of doing ..
my bike has no instrument cluster
The ignition switch Ive used for several years with no problem (the original packed up and spare parts are not available in Thailand also expensive to import..
The wiring loom purchased is plugged up exactly plug to plug with correct colours.
When the starter button is pushed the voltages do adjust as they should be.12volts and down to 4.9 volts as I explained before.
My problem is the starter doesn't turn I have I have the correct plug at the starter relay and the relay tested ok.
If I remove the start relay and touch the wires together the starter will turn .
My question is where am I going wrong ? Is there something that needs to be connected at the cluster plug ?
The wires for the clutch safety are connected...
I hope this helps you understand Mr.Laitch.
I am British and if I lived in the UK I'm sure I could have help from my friends but that's not the case I have no support and as you noted the bmw does have a very complex wiring system which is why I abandoned the idea of cafe loom and returned to standard..many thanks

I

Oh and I feel confident I can remove the ABS section of the loom but haven't at this time as I don't want to open up and start cutting wires until it's running

I

My goal is to start the bike but first I need to check I have a spark .
The fuel tank is not fitted at this time

K bike does not run without the instrument cluster.

not sure about that , i ran one for @10 years with no clocks

firstle wrote:not sure about that , i ran one for @10 years with no clocks

Time must have stood still.

Craig's right. When troubleshooting LFB few months ago and I decided I needed a new wiring loom, I built one that just allowed the engine to start and nothing else. There weren't even any connectors on it to push into the instrument cluster.







Turned out it wasn't the wiring loom.








It was the bloody thermostat on the engine

i just unplugged mine when they played up and pushed the plugs under the tank , i alway ment to replace them but 1000s of miles latter did not miss them , wish i had kept the bike it was my first k100 1984 ex police . it ran faultless

Ribi wrote:Thanks for your reply but what don't you understand?
My problem is the starter doesn't turn I have I have the correct plug at the starter relay and the relay tested ok.
If I remove the start relay and touch the wires together the starter will turn .

I don't understand why you believe a 12V starter should work receiving 4.9 volts—if that is what's happening. On the other hand, your sentence structure has improved and is easier to read.


When you write "the starter will turn" when the relay is not in the circuit, is that indicating that the starter motor is spinning but the crankshaft isn't turning?

It's clear to me you need to review all your wiring connections using the electrical wiring diagram that's in the Tech Page located in this site's Portal, accessed by clicking Portal button at the top of this page. When you find the wiring diagram link and open it, click on the box at the top of the page labeled Starter and compare the circuitry with yours. It's K100 wiring but yours is the similar..

I think you're saying that when you bridge the red and black wires at the starter relay, then the starter turns. When the start button is pressed, this relay should be supplied with power from the black/yellow wire, and earth from the brown/red wire. Maybe it's not getting earth. Connect a temporary earth wire from the brown/red wire to a good earth point on the frame. Give that a try.

Ribi wrote:Help needed too many photos

Click on one of the unwanted photos. Press the backspace button a few times. That should do it.

Thanks daveyson I can do that many thanks couldn't delete photo so please just Ignore them
Thanks to anyone with positive help
Mr Dai. Would you mind sharing the info concerning running the engine on a short loom
Mr Latch. When I press the starter button I get 12+v to relay but believe by pressing the starter it also passes a lower voltage to activate the ignition system (very complex for someone like me) from the relay not before it ....do you understand ? or am I wrong ?
Now I'm going to put the battery on charge so I can do some correct measurements tomorrow and check Mr Daveyson suggestion .
Now I'm going fishing ok

Thanks daveyson I can do that many thanks couldn't delete photo so please just Ignore them
Thanks to anyone with positive help
Mr Dai. Would you mind sharing the info concerning running the engine on a short loom
Mr Latch. When I press the starter button I get 12+v to relay but believe by pressing the starter it also passes a lower voltage to activate the ignition system (very complex for someone like me) from the relay not before it ....do you understand ? or am I wrong ?
Now I'm going to put the battery on charge so I can do some correct measurements tomorrow and check Mr Daveyson suggestion .
Now I'm going fishing ok

Ribi wrote:Mr Dai. Would you mind sharing the info concerning running the engine on a short loom

That's.... difficult because I still had to build around 60% of the loom to connect all of the required parts together. Effectively, you take the diagram of a standard wiring loom, then remove all the lighting, the horn and the parts that go to the instrument panel. What is left is what you need.

Ok Dai,thank you anyway I do understand I pretty much done the same but it is to complicated for me
Mr.Daveyson ok today had good Earth's to both the brown/red and the black /yellow wires which do go live at 10.14 volts until I press the starter button the volts go to 13 v at both terminals but still no starter motor..
Please tell me if I'm correct in thinking when the start is pressed the black wire bolted to the relay should go live suggesting the relay may be at fault. ( I had the relay tested at a shop and they said it was ok )
Many thanks for your input I will try another relay tomorrow as your day starts mine has ended now and it's too bloody hot now

It seems to me that pin 86 (black/yellow) should only have power while the start button is pressed.

Yes sir Mr Daveyson that's what I have.
I've sent a photo of my ecm inside I don't know what I'm looking for but it doesn't smell and I cant see any obvious damage.
Also a photo of the volts at ecm after starter button pushed.
Relay swap made no difference

I think you want to focus on why the starter relay isn't doing it's job. When you press the start button, you should be able to hear and feel a click from the relay.

Yes, when the start button is pressed the black wire should go live.

Hi Mr Daveyson Sir.
Wow so today gotta chance to work on the bike .1 st I thought to clear up a bit check the plugs are clean and in the correct places...nothing out of place so I've done enough today ..
I do recall you saying test the brown/red wire at relay for earth and it wasn't there so I jumped an earth from an accessory plug in the relay box.
Hey presto your the man I pressed button starter swings so I turned it all off and stopped for the day it's really hot and my dog needs a walk..so thank you sir I will now check for sparks and fuel tomorrow if I have time

Just 1 question please I recall my bike never ran without clocks I tried years ago but there is conflicting information do you think I should use a false neutral set up like the 3 relays hooked up together?? Thank you

If you pull in the clutch that closes the clutch switch which sends 12V to the start button. The other thing that sends 12V to the start button is when the bike is in neutral and the gear indicator in the cluster sends 12V out to the start button via Pin 6. 

Both are BLK/GRN wires to Pin 6 of the right combo switch connector.

Summary: Without the instrument cluster a K bike will only start when the clutch is pulled in.

Assumption: Clutch switch is working.

unplug the instruments (mine filled with water) and my 1984 K ran faultless for years

I'm in agreement with duck here. It sounds like there have been examples of bricks running without the cluster, they might have had the wiring altered to suit. If it's a no-go without the cluster, a simple solution is to pull in the clutch before starting.

Hi everyone im happy to report they do run without the clocks with some electrical adjustment
Now the bad news it's over fueling I've put the injectors in a catch bottle to look I'm not a professional in the fuel injection but it looked like too much !!
Next question is what do you gentlemen think I should look for. Many thanks it was great to hear her run
Ps I put a paper clip in 5 and six in the cluster plug and joined the clutch wires

Hi gentlemen,ok so you helped me start the bike but now it's really flooding the spark plugs and filling the exhaust with fuel..
Previous to accident ran perfect...so I replaced the wiring loom because it was damaged ( by me)I also made the mistake of fitting battery in reverse (idiot me) just momentarily (yes it did melt wires to alternator)I've replaced the wires..
I've opened the ECU a look ..no unusual smells or obvious damage so now the bike will start but over fuels and cuts out...
I did read only damage(if your lucky) is to wiring at alternator..
So can someone smarter than me please help find my reason for flooding ? I made a catch bottle to put all injectors in and they spray hard ,,I have 12v to one side of injectors and ground to the other side
Also after realizing my mistake I used my original fuel harness to eliminate any loom problems .
Any ideas guys and thanks for looking I am in Thailand so no technical help available it's up to me to learn by doing which I enjoy

Check the resistance, one injector must be 4 Ohms.

Check the fuel pressure regulator, if it's defect it may cause injectors to leak.
You need a fuel pressure gauge. 2,5 bar is needed.

Check the engine temperature sensor. If it's not correct, il may send bad informations to the ECU and it then considers that the engine is cold, so it enriches the air fuel ratio.

Also check your vacuum line to the fuel pressure regulator [FPR], if that is leaking injectors will over fuel. If the diaphragm in the FPR fails no 3 cylinder can suck in petrol through the vacuum line.

If you have issues with wiring to the temperature sensor [behind the radiator] it may think the engine is running cold.

Do the injectors pulse on and off when the engine is running? 

If not, unplug the injector connectors and check the resistance between each of the pins and ground.  There should be high resistance.

The injectors work by having approximately 9 volts always on one of the terminals and they are turned on when an output transistor in the Engine Control Unit turns on and grounds the other terminal.

When you connected the battery backwards there is a chance that transistor burned out and has an internal short circuit that has the injectors turned on all the time causing over fueling.

Topics merged. Same bike, ongoing issue.

Nice summary Mr Yes two wheels are better but I'm getting there I'm very busy for a few days but was just have 5 minutes and checking in...
There's some good imput by members I want to do it now .
By the wat I had 12v at I side of injector and ground on the other
There's no water in rad
Ad injectors don't pulse they spray hard quite hard
I have replaced all pipe work in the tank also and vacuum pipe
I haven't been able to do a pressure test..
Confession time when I got my bike many years ago and because there are no spare I was told the fuel pump was changed for a Toyota fuel pump it's always worked I've only seen it because I'm looking for a problem
If your still reading I did notice broken fuel pipe ( which I'd be happy to see if I had a low pressure problem

I also found the vacuum pipe had perished inside the protective spring...so I changed it!!

Any suggestions for me please I am back on it now ! Many thank