I just couldnt believe it ! Yesterday , everything finished on bike, final clackity valve noise adjusted and now quiet , said to Alison how pleased she will be that the days,weeks,months even, of me stuck in shed swearing at bike parts have finally passed, first drive with "it all done" , imagine my excitement on that first glorious day!

200 m up the hill ,burning rubber smoke comes from right handlebar switch consol and then from wire loom connecting consol to control box.

Now am back in shed swearing at bike parts and after such a short reprise bike is now not in one piece. The culprit is the headlamp wire which has burnt out, but interestingly the headlamp works when turned on for a couple of secs to identify the smoking wire. So off with tank and remove the loom i suspose . My question is do you think i will need to replace the switch unit and loom or simply try and replace burnt out wire ? Also,is there a possible underlying fault somewhere ,or is it a 23 yr old loom decaying ,or could it even be the (ooops) naughty pressure washer used by someone immed before that first ride !?

Any advice gratefully received

I can sympathise with you on this issue, when I purchased my K some clever person had fitted a 140/90 watt (yes you heard me correctly) headlight globe. K's have quite light wiring and the headlight does not have a relay close to the globe so all current must be carried by the wires through the loom. Possibly a shortage of copper in Germany at the time ! I happened to find my hedlamp hi/low beam switch and wiring harness cooked. New switch assy complete with loom, and replaced the wire down the left side of the under-tank loom, very frustrating.
So I would advise to take a look at the headlight globe, it may be the problem. It should be a 55 watt H3 I think, Bert please correct me if I'm off the mark here.

Regards, Dennis

Jonny, I am very sorry to hear about your set back

Dennis wrote:It should be a 55 watt H3 I think, Bert please correct me if I'm off the mark here.
Regards, Dennis

Dennis, you are quite right. 55 watt is the safe maximum for the K100 wiring.
The problem is that the power pass through the switch assembly and the contacts are not designed for more than 5 Amps. With a 55 Watt bulb, the amperage is 4.5A. The other problem with a 90 Watt bulb is the headlight socket. The original one is plastic and will melt with the heat generated by the bulb.

Naughty pressure washer is to be banned on the K100. This is how people burn the cooling fan.

The hand switch assembly and wiring loom will have to be checked. In the download section you will find a small tutorial to open and fix the switches.
Even if the bulb is the original it would be wise to upgrade the light circuit.
The best is to have a good size wire coming from the battery (with an inline fuse -or a breaker is even better-) as the main source of power for the headlight. The original headlight wires should be only used to energize the coil of the relays.

Good luck on the repair.
Bert

Gentlemen thank you

The bulb is a 90/55w H4 37R.

The damaged wire was the blue/grey headlight wire. The plastic coating had been almost totally melted throughout the loom damaging several other wires in multiple places.Goodbye loom!

So I need to get another unit and loom. Do you think the bulb wattage was responsible and also might it be of interest to disassemble the switch unit .

once again best wishes and thanks
jonnyqq

If you go to http://www.easternbeaver.com you will find a very well made plug and play kit that fixes the headlight problem in an instant and if you wish to run higher than the standard H4 60/55 you can get an uprated kit or one that allows for additional driving lights.

Mine was originally running a 100/90 and did not do the Hi/lo beam switch any justice and as the K does not run any relay for the headlight it is not the greatest bit of engineering.

I bought the Eastern Beaver kit (great guy to deal with by the way) and was really pleased with the quality of the kit. I bought the heavy duty sealed relay, ceramic socket kit and it really is plug and play. I now run a big bulb up front and no problems with running on main beam all day and dipped at night (also no problems with the headlight shell either).
Regards,
K-BIKE

thanks
had a look at website , it does look fairly idiot-proof so i reckon that might be easiest option for me ! Berts`option would obv be the best one but frankly my confidence levels for electrics are at best challenged !

I am really at home with electrics having worked on cars and bikes all my vehicle owning days, including building a couple of cars and bikes from scratch and making up the looms. That said the Eastern Beaver kit with the sealed relays persuaded me to give them a go plus the ceramic holder just made it a no chasing around fix to a problem. I really wanted to run a brighter light and doing that with the standard set-up puts all that current through the switchgear which on almost all bikes not just the BMW are frankly crap, (that's a technical term). With a relay assist it is well up to the task of driving the relays for a very long time.
Regards,
K-BIKE