1984 bike replacing the loom.

After speaking to olaf tonight I've agreed to post here to see if anyone can help me. On tuesday I was riding home and the battery light stayed on. Ended up breaking down about a mile from work. Luckily a workmate pulled up next to me. This is when the bike caught fire under the seat. Taking part of the loom with it. Fortunately we had a fire extinguisher at hand and managed to put it out. Nothing else has been damaged.


Looks like the alternator wire had singed and earthed on the frame causing sparks.

Fast forward to now and I'm trying to fit a new loom onto the bike without having much luck. Basically I'm stuck with the cables underneath where the tank sits. Didn't take any photos.

Has anyone on here got a simplistic list of what cable goes where under the tank. Pressing the horn I get nothing currently, pressing the indicator all I get is a large beep. The oil light and coolant light stay on at neutral but there is no battery light what so ever.


(at the moment I'm reduced to a 50cc chinese moped to do 20 miles a day commuting including two large hills).

If you look on the front page of the portal under the EFI/Electronic ignition and troubleshooting, there is a diagram of the under tank connectors and ground.  

That may be somewhere to start.

Go to the manual here:

http://www.motobrick.com/index.php?topic=11014.0

and then there are some drawings starting at page 403 which should be helpful.

Complete color coded wiring diagram for early K100:

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/kwiring/Early%20K75%20K100/K100_Early_Wiring_Diagram.jpeg

Post 9 here: https://www.k100-forum.com/t10428-comberjohn-s-ghost

Afraid I've been trying to get this loom to work and it doesn't even to be from an early k100. At maximum I'd say k75. Now just wondering does anyone kniw where I can get a spare loom from.

Tried motorworks and james sherlock not having any luck so far. The other uk based company is motobins and they don't stock them apparently.

Sorry for the delay to the post been working long night shifts.

I just sent an Email to a guy selling used k100 parts and I will let you know if he has one.
I have another contact in France if the first one doesn't have it.

CF

Here is something for you. Dirt cheap.
Loom for 25 Euros

Crazy Frog wrote:Here is something for you. Dirt cheap.
Loom for 25 Euros

Thank you I purchased it this morning. Couldn't seem to get onto this website at work. Either way should be sorted soon thank you again.

Well I've got the loom from the one linked by crazy frog and I'm having problems with starting the bike.  There is currently nothing at the switch. I'm guessing its possibly the way I've put the cables onto the coils.

Did take about 20 photos before I started this but my phone was on messenger at the time so it didn't save them.



Any help would be grateful, lovely sunshine this week and the bikes not working. Typical eh.

Can you offer a bit more detail?  Based on what you have posted, the only suggestion I can make is that you hooked up something wrong.

Not sure if this will help but here's a picture I have of early K100 coil wiring:

Nothing at what switch?  Ignition switch?

Point-Seven-five wrote:Can you offer a bit more detail?  Based on what you have posted, the only suggestion I can make is that you hooked up something wrong.

Had the loom set on fire, I've replaced it with another loom of the same year. From a known dealer so should be 100% good. Lost the photos that I took originally when I took the original loom off. So I've hooked everything up the best I can trying to go colour coded.

I've taken some photos to show how it's wired up encase anyone can see anything that I've done wrong. 

Everything is woking that I know of without a running engine. Horn, indicators, headlight

However when I turn the key all I get is a faint click from the relay area. Then nothing pressing the starter button. The starter motor is good and so are all the relays. It all worked perfectly before the loom was removed it's just the alternator wiring was burnt through.

To be honest it does seem that something has been wired up completely wrong.

about the coils:

Ground (brown) and signal (black/red and black/blue) is interchanged.
Also the signal wires is interchanged, blue should be at front coil (1-4) red at rear (2-3).

Does the N indicator in the cluster illuminate when you have the bike in neutral?  If that lights up then it should be sending 12V+ to the start button.

The other thing that sends power to  the start button is pulling in the clutch lever.

If the start button is getting power and working then it will send 12V to the black/yellow wire on the starter relay when pressed.

The starter relay gets its starting power from a large gauge red wire that is always hot.  Be VERY careful with that wire as it is not fused and connects more or less directly to the battery. If you ground it by accident it will not be happy.

There is the problem thank you. No power to the yellow and black lead. Now to try and find out which connector that is further up the loom.

Black/yellow wire goes from the right combo switch connector to the starter relay. The only connector in that path is the right combo switch connector.

(And the other black/yellow wire from the right combo switch goes to the ignition control brain under the front of the tank.)

Thank you duck managed to get her to crank just won't start yet. Going have to look at why the battery terminals are getting warm as well.

So checked the fuse and on fuse 6 (fuel pump If im correct there is no power).

Right then she is running however no battery light and she is charging at 12.9 volts. Can't seem to narrow down the problem the alternator itself is reading 12volts as well. Regulator has been changed for a known good one.

Edit....

If i put a wire onto pin 31 to a3 of the relay holder I do get the light on the dash.

However the bike then cuts out when too hot and refuses to start.

Have you tested the bulb in the instrument cluster and confirmed that it is not blown. According to the first post, it was operating before the fire, though that doesn't mean its operating after the fire. If the bulb is blown, 12V won't be applied to the field coil in the alternator and the charging system won't operate.

Both bulbs are fine I've replaced with brand new. As said above I can get the temp one to come on. But only with the wire shorting it. Still no luck with the battery light.

Did manage to get the fan to work which is a bonus don't know how.

To check the dynamo warning lamp circuit....remove the connector on the
rearside of the dynamo and ground the blue wire.

Carry out the test with ignition on and engine off.

Inge K. wrote:To check the dynamo warning lamp circuit....remove the connector on the
rearside of the dynamo and ground the blue wire.

Carry out the test with ignition on and engine off.

Cheers inge I pulled the alternator and put one in from my new project k. It's now working at 13.9volts. The regulator is old and tired but cleaned up. The battery light now goes off and is charging so I'm happy.