Hello,
Well after managing to get the (recently acquired '85 UK registered) K75C on the road, have enjoyed a few miles today (about 80) to see how it went; and seems very nice.
Think my mass needs the suspension on a setting far away from the lowest position but apart from that ride was smooth and comfortable with the C bars and low seat; another bonus was not tipey-toe at junctions.
Two small 'issues' related to the instruments, that I wonder if anyone can advise over.
1. The LCD for both the clock and gear position seem to have had it and (for the clock) missing some digits and the gear indicator just changing patterns - assume there is no fix for that.  :| 
2. The other, found there is no 'knob' for the trip meter to adjust; anyone know if the knob is a part that can be ordered and can it be replaced if missing / fitted   
Mind u, two small(ish) minor niggles on what otherwise seems a good bike - and less (price-wise) than some pushbikes/cycles   
Kind Regards
Mark

The small LCD panel(s) itself can be removed and the contacts cleaned,
you find some posts about it if you use the search function.

The trip reset knob you get as a set, knob/spring/lockring/o-ring.

yep mine committed harikari and lept off somewhere along the road

the bins and motor works have the parts ..

Inge K. wrote:The small LCD panel(s) itself can be removed and the contacts cleaned,
you find some posts about it if you use the search function.

I think both Rick G. and Sidecar Paul have posted about this.

Yes Inge,

 Missing segments on the clock may respond to this:-
https://www.k100-forum.com/t4319-clock-repair?highlight=clock+repair

Paul.

Inge K. wrote:The trip reset knob you get as a set, knob/spring/lockring/o-ring.

Thx, thats looks promising.
As I have no trip reset knob at all wondering if the/a replacement one can be refitted without dismantling...as that scares me a bit   
And apart from the LCD, as its working I am a bit scared of breaking it   
- hence wondering if the reset knob can be fitted without dismantling. I saw a post that shows a picture of the knob and also on motobins site; but not the procedure for fitting (and that doesnt seem to be detailed in the Haynes manual or any posts I can find).
Mark

Sorry, but you must tear out inner guts when mounting the reset knob.
The spring and lock ring is mounted from the inside.

How to take the cluster apart, have a look a bit down on this page.

Inge K. wrote:Sorry, but you must tear out inner guts when mounting the reset knob.
The spring and lock ring is mounted from the inside.

How to take the cluster apart, have a look a bit down on this page.

Thx for advice and link. Guess if I get the part will have to be brave....and take it apart.
Regards
Mark

Fixing glowing telltale light on K models
Service bulletin 61 021 89 (2354), issue April 1989
Subject: Telltale light glows-K models
Condition:
Battery charge telltale light glows very dimly, even though engine RPMs are at highway speeds. This condition is most noticeable at night and when heated grips are used.
Information:
Testing the charging systems proves that the charging system is working properly and no fault can be found. The purpose of the charge indicator light is to inform the owner when alternator output voltage equals battery voltage. This is done by providing battery power (gn sw) to one side of the indicator light. The light grounds (bl) through the alternator diodes until alternator output equals battery output, thereby providing a positive on both sides of the bulb, which makes it go off.
Cause:
The light may glow (particularly with the heated grips activated) because some resistance has developed in the connections on the (gn sw) side of the circuit that slightly lowers the circuit voltage, so that a minor voltage difference occurs. Heated grips' consumption exacerbates this resistance sufficiently to produce a drop of perhaps 1/2 to 1 volt, which makes the light glow. This condition does not affect the output of the generator.
Remedy:
Although the system will work perfectly without any change, it may be annoying to the rider. The simplest way to correct this condition is to install a diode in the blue wire. This will eliminate any backfeed if the voltage drops slightly on the system side (gn sw) of the circuit.
Installation of Diode:
Diode--part no. 61 31 1 358 268--can be installed near the alternator. Cut the blue wire approximately 2 inches from the plug-in connection at the alternator and splice in the diode. The diode and splice connections must be protected from elements with heat-shrink tubing or electrical tape. OR The diode can be spliced into the blue wire inside the electrical equipment box under the rear of the fuel tank.
Direction of Diode:
The arrow on the diode must face towards the alternator.