While on our Sunday Ride I had a lil gremlin surface. My charge light came on and the Tacho and speedo started to float up and down. when I stopped the bike it would not start as the 7.5 amp fuse had blowen. On replacing this fuse it was all good getting home and during the week. This morning I goes to head for a long ride and the charge light came back on..Now the odd thing is this . it only came on and the tach and speedo floated when I used the front BRAKE!! I headed for home and only used rear brake and no charge light!! stopped the bike when I got home and the fuse was blowen again.

Off with the Tank (again) and into the connectors to follow the brake light wires. Nothing seemed out of place. I decided to clean up some of the old connectors on charlies advice and found at one time they had been very hot under the old tape..




So I set about fitting new plugs and some heat shrink leaving enough old insulation to identify the wires. Crimped and soldered connections now.



With new connectors in place and all the others clean I am almost certain that my ignition barrel is the culprit. i can shake it about and get a rather 70s disco light show. it also gave me lights and no power and other odd doings. going to have to wait for the new unit to arrive to see if that is the nasty.

On charlies advice i also cleaned my starter brushes again and he may be right (more praise for you old mate!) they need to be replaced! I have recently changed the bearings in my alternaor and fitted a new regulator. The battery seems to be well charged and holding around 13 volts. All earth connections have been given the treatment and i am open for any other suggestions. One more thing. Does anyone have an earth wire from their bars to the frame? (charlie mentioned this as well). I think I have a Charlie syndrome!!!! Best stop listening to people

If you dont have that earth wire from the right switch unit to earth the throttle cable can overheat because it is used as an earth and when it gets hot the plastic inner liner melts and the throttle jams. A very fast ride and extreme bum puckering takes place till the key is turned off.

This additional ground wire K-Freak mentions came as an update from BMW in 05/84.

Inge K.

good work alby .....lets hope those fuse blowing days are over mate ....



hey i'm only an old bugger hoping to help you to the bliss that the "k" bikes are ....



happy riding !!!

Hey Alby, there's a switch on Fleabay at the mo...and I've seen the odd switch rebuild write-up around the traps too.

Cheers Blakey. I did find that, but have decided to give her a new shiny one. The barrel on the current switch will accept any key offered ATM. all are loose fitting and cause the same light display on jigging the key.

When I fit the new 20mm master cylinder recently I disconnected the earth cable from the old and could not locate an easy-to-mount-it-to place on the new...so I left it loose under the 'dashpad'. You can be sure that I'll connect it straight away tomorrow morning before any more riding is done. Ta for the tip.

The things we learn on here, bloomin wonderful nice one alby.



BIG D

Hi Alby!

I see that it`s the the wires that goes forth and back(low beam) from the dimmer switch that is fried, running on a heavier bulb than standard (or just bad connection at the multiconnector)?

Anyhow I would advice to get a couple of relays installed in this circuit to get less load on your dimmer switch (easily fried even with standard bulbs, have repaired a whole bunch of them).
It`s space enough inside the relay box, where signal for high and low beam allready is present through the additional socket (yellow wire=low beam, white wire=high beam).

If it was only yellow/white and yellow that was fried (by judging the pictures) I don`t think it`s related to your fuse blowing, since the light circuit are unfused.
Which fuse # was blowing?

Inge K.

the top fuse inge = instruments etc and a few other things i believe (accesory socket , stop light , bmu, f1 and kill switch )


i hope that there isnt a short in the handle bar cabling that hasnt been found yet . like the kill switch wiring maybe ?.

i think i would be running an earth cable to the right hand switches with the eye attached at the 4mm allen bolt on the brake master cylinder front side like the later models .

and taking apart the stop light assembly for a visual inspection , and replacing the bulb as a minimum .

the onside of road fault looked exactly like the kill switch had been activated .

(even thinking to myself that i should add an aditional fuse block to divide up this load at this point with clearly marked fuses )



i think im going to carry a copy of the fuse layout (thanks cf ) in my under seat kit of electrical spares, laminated of corse.

good tip about the relays also (done mine)

For some old bikes which did not have an earth wire to the bars they relied on the bars being an earth which meant the head bearings became a conductor and that was one of the things which contributed to early head bearing failures.
Regards,
K-BIKE

charlie99 wrote:the top fuse inge = instruments etc and a few other things i believe (accesory socket , stop light , bmu, f1 and kill switch ) i hope that there isnt a short in the handle bar cabling that hasnt been found yet . like the kill switch wiring maybe ?

Kill switch and FI is connected before the fuse, I would suspect rear brake light switch (a tight place behind the right footrest plate, with clips etc.....more owners have experienced a short in this area), try to run the bike with this switch disconnected for some time.

About the suddenly stops (like kill switch activated), Alby have admitted a sloppy ignition switch, I would suspect that is the reason.

One fault triggers the next....connection at ignition switch just can carry the load....rear brake light switch (or whatever) shorts....
fuse blows to late.....ig.sw. overloaded....................it`s all in the same circuit.

Inge K.

If it was only yellow/white and yellow that was fried (by judging the
pictures) I don`t think it`s related to your fuse blowing, since the
light circuit are unfused.

Way ahead on this one. have the relays already to go and a fused 20 amp power supply in place. The heat damaged insulation was noticed last weekend and once i peeled the harness tape back found a bit more of it. I got a little of topic with them. Just showing off the fix and new stuff!!

I am going to put the earth wire on the bars first and open/inspect start kill switch. Also try and see what sort of readings/shorts i can get from the ignition key barrel to earth. I wil also investigate this brake light switching. I had a problem a few weeks ago of the front brake light switch not opening properly. Brake light on all the time but fixed by cleaning out switch.

Still got a gremlin in there. I have fitted the new switch (boy it feels good, Charlie was right again. Nice to have park lights turn on/ off and power when its meant to be there with the exception of the gremlin)) also headlight relays are in and working. Still got a fuse blower. I have narrowed it down to the Brake light circuit. i did this buy using a lot of fuses!!.

When I engage the front or rear brakes i first get the dimming of the display lights then the charge warning light and the fuse blows. This also happens with the brake light disconnected at the posative side of bulb holder. Lights on or off. Engine running or not. Everything works as it should when the fuse blows except for the display lights. The engine still runs and as far as I can tell the alternator is still charging as my battery is happily sitting on 14 volts while running.

I am going to try and see if i can find a short between the brake light and the brake pedal/lever switch tomorrow. Anyone got any suggestions?

as inge suggested alby ...there are 2 clips that clamp the brake switch cable to the frame as it leaves the rear master cylinder ....the cable then snakes its way along the frame to the right hand side cover ..there abouts .

dont move that cable too much at this time ...we want to find the short ...and "prove it "


what you could do is disconnect that cable at the join and put your multimeter on one of the cable connections (red lead ) select ohms on the scale and put the black lead of the multimeter to the frame .....if this is the faulty section you should see the meter go close to 0 ohms ....of corse you might have to operate the switch at the same time ........time for the "magic third hand " maybe a aligator type clip lead could joint the multimeter probe and the cable connection ...if you have one handy ...same with the earth connection to the black lead .

depending on which wire you connect up to either the short to earth will already be there ....or it will be when you operate the switch .....switch leads at the connector to test this



good luck !!!!

The cables to the rear brake light switch may have become trapped behind the footrest plate and be cut/worn through. Then again maybe not, but it is easy to get them trapped when replacing the footrest plate.

Ah yes I know how to trap them behind the foot rest, it's a good trick:oops:

if nothing is found at the switch ....continue on my friend ....the next location could be the under seat area where the cables head towards the rear light ...at the back of the frame the cables do a little switchback and enter the tail assembly .....i remember undoing the tail light and found some exposed connections in there ,,,i reconed it should be safe as there is basically fiberglass around there ....but ....check the cable for compression or even perforation at that area of the frame / ducktail entry ....even check the connections around the globe/lamp assembly

Easiest way to narrow down the search would be to disconnect the BMU, and measure at the connectors in the socket:

Terminal E1 (grey/red wire) front brake light switch.
Terminal E2 (grey/green wire) rear brake light switch.
Terminal 54A (grey/yellow wire) brake light bulb socket.

Measure the resistance between ground and these connectors, all should be infinite ohms.
And if they all do, it`s the BMU itself that is the bastard.

The BMU you can leave out (until you get a new one), just bridge the connectors.
How to, check close to the end in this thread.

Inge K.

Charlie.....PM for you!!!

Success Found the LIL Blighter.. Took a bit but I found them!! After working through all the advice given I found i had a direct short to earth on the power side of brake light bulb. I could prove this, So following the cables back from the brake light I came across >>>>
This Looked SUS!!!
Looks a lil squashed!!
A very small hole was showing conducters in this patch. have a look at the brake light cable.

Spliced and soldered and covered in heat-shrink. All Fixed Now.
Moving on I found one more short. It was in the rear brake switch but was caused By some Great Bird not taking enough care. new one on its way.

I also fitted a new set of starter brushes after a miss-intended donation of parts. A complete Controll unit cover as well for a whole 2.00 aussie!!!

Learnt a lot from this and hope someone new can as well. But as i have found, read all you want but nothing beats learning by doing!

Thanks for the help guys!!!

Good job and like you said there's nothing as good as doing it yourself for learning.

omg ....nice work alby .....cheers brother !!!

After a 4 hour ride out through brooklands across to crows nest and into Toowoomba for lunch i am confident that i have a FIX!! (Now to get Nics heated vest down from 42 deg Cel.)

lol ......ill bet she'll appreciate that alby ....poor gal

good luck nikki ....just make sure that he traces the cables for shorts ...before you put that vest on ....

might come in handy over the hills down south

What brand is the vest? I have a spare adjustable thermostat for a heated vest that I don't use. Liz rides with it just as an on/off switch when she uses my heated vest.

good luck nikki ....just make sure that he traces the cables for shorts ...before you put that vest on ....

What brand is the vest? I have a spare adjustable thermostat for a heated vest that I don't use.

Its Alby Built. (Short Free). Going to whack a resistor in series with the switch on the output of the Pulse Width Modulator I put together yesterday.. It will let me give her a variable thermostat of sorts. Actually it will be fixed so I am in some sort of control of the power she uses .
She still on the floor LHAO!!!!!!!!

giggles ....

Albyalbatross1 wrote:


Its Alby Built. (Short Free). Going to whack a resistor in series with the switch on the output of the Pulse Width Modulator I put together yesterday.. It will let me give her a variable thermostat of sorts. Actually it will be fixed so I am in some sort of control of the power she uses .
She still on the floor LHAO!!!!!!!!

Just so long as she approves hey.