Hi all,
 
I have now been driving my “project” motorbike for more than 1000km. That period gave a me a good insight to its condition and what needs to be done during off season. It has now been driven 72000km (only if readings are correct). Already made a list of critical parts to be purchased. Most of them are various rubber parts like piping, gaskets, axle seals, grommets etc. Forum’s techpage has been a great help along with Clymer service manual. 
 
One of my concerns is the color of the bike. Last week I visited my friend who is a car painter. Idea is to get all fairings repaired and resprayed as well as all black painted engine covers (front and sides) and fork tubing refurbished. With this renovation project, it is possible to change the color of the bike. My bike is now Black (basic, not metallic) and in fact it is a bit gloomy  . If I do interpret 1985 K100 Colors chart right (techpage), there are 5 colors available, right? Are these only factory colors also for year 1986? 
 
There are also some other concerns. Bike is creating a blue smoke on a startup. When engine has been running some time, there are not anymore smoke. It does not matter whether the bike has been on a center or side stand. Engine runs and responds to a throttle well. Despite of this, I plan to do a compression test first and then decide what to do. Firstly, I suspect worn valve stem seals as they are 34-year old. What a coincidence that according to part number BMW has used same seals in some BMW cars of that time. Same case with rubber caps in a throttle body. 

Ignore the blue smoke, its because the engine is on its side. Just shut off the engine before putting it on the side stand. That oil is seeping past the end gaps in the piston rings, the rings are not pinned. It is not coming past the valve seals.

Agreed that the rings are the likely culprit in smoking. It was a later series production (1988 or so) that had the piston rings 'pinned' so that the end gaps didn't float round the piston to the bottom side of the cylinder bore, allowing some oil to creep past when stopped and tilted down on the stand. Yours is a 4/86 production date according to the VIN, and therefore old enough to smoke!

Having said that, my 10/86 RS doesn't smoke when left on the side stand.

HERE is what realeom.com says are the colour options for your bike's year and VIN.

Hi,

Thank you for your comments . I need to evaluate the colour of the bike once again. My primary intention is to get the bike museum registered some day (at least I prepare for it). This requires the bike to be painted in an official colour. Anyway, black colour is a bit gloomy when its surface is covered with scratches - a lot of those. I do not like it.

As for smoking, I do believe (according to your comments) that the primary source might not be valve stem seals. Let's see is there any need to dig in deeper in the engine. Btw, are newer piston rings compatible with my old bike (pinned ones) or does it require new pistons as well?

JiiPee63 wrote:As for smoking, I do believe (according to your comments) that the primary source might not be valve stem seals. 

You can always do compression and leakdown tests to track the source.

JiiPee63 wrote:Hi,

Thank you for your comments . I need to evaluate the colour of the bike once again. My primary intention is to get the bike museum registered some day (at least I prepare for it). This requires the bike to be painted in an official colour. Anyway, black colour is a bit gloomy when its surface is covered with scratches - a lot of those. I do not like it.

As for smoking, I do believe (according to your comments) that the primary source might not be valve stem seals. Let's see is there any need to dig in deeper in the engine. Btw, are newer piston rings compatible with my old bike (pinned ones) or does it require new pistons as well?

You have to change the pistons too. A lot of effort for very little return. If you fancy a little boost you could use K75 pistons as they are higher compression ratio.......

Thanks , I realise that it does not really make much sense unless there is another reason. I hope not...