I guess I am one of the oldies her. Being a grandfather at 63 I still love to ride my K100RS to work ( and back )
My first bike was a NSU Supermax. Then a Honda 500 four, a Honda CX, another Honda and a Yamaha XJ900. Then finally a BMW. The first one, a K75, was a waste.
Lucky me that I got hit by a car and my K75 was total loss, and with the money I cashed thrugh the insurance I bought my K100RS, now 7 years and 95 000 km ago.
Recently the old lady (1990) let me down for the first time.
It is probably a small issue , I normally do all the maintenance myself, so I know she is in a good condition. I hope to ride her soon again!

Hi Motorbelg and welcome to the forum.

As for oldie, I also had a Honda 500 Four and a CX......Comberjohn will probably be here too and he also had a 500 Four....

Everyone is very helpful so do feel free to pop up a question on the problem. What may seem a small thing someone will have the answer. We will need, ideally the VIN number so everyone will know what things are correct. I think that whatever problem you have someone will have met if before!

We do also get to meet up a bit so if you are game for a few travels then you could really enjoy the forum.

Are you far from Antwerp? My daughter lives there for now....and we fly from Brussels...Just checked, was in Roosendaal, not far from you!!!

Hello and I'm another one who had a Honda 500/4 - I thrashed it everywhere and apart from the ignition switch falling to pieces on the way back from the Lake District one day, it never let me down. Can't remember what happened to it now..

Old at 63 - I think not. I hope to be ready for my forties by the time I get there!

Welcome to the Knut haus!

88

Welcome from the USA.  I think you're in good company; lots of grey beards here I expect.
I'm surprised to read the K75 let you down.  There are many who insist the K75 was one of BMW's great successes.  I've never owned one, so I'm just a bystander in that debate.

88KE wrote:Old at 63 - I think not. I hope to be ready for my forties by the time I get there!

Welcome to the Knut haus!

88

This is the ex 500 Four owners section. This space is reserved for Comberjohn...

Funny...my ignition switch was the only thing gave up on it....largely due to me relocating it up in the clocks. Oh, it needed new pipes too. Ouch. Cant imagine scraping the pegs on the K they way I scraped them on that.

Hi Motorbelg. I think we are pretty much all oldies here. Hope your 'Old Lady' gets back on her wheels soon.
WeKome to the forum.
Cheers from DownUnda

Welcome to the play pen Motorbleg. Old is 10 years older than you

Welcome to the forum from another "young" Knut. Age means nothing to us....we can't remember anyway. Remember that never be afraid of old age...it doesnot last long.

Thanks for all your warm welcome greetings!
Now I feel free to drop my bike's problem!

I rode my bike to work in the morning, everything smooth as always.
In the evening I could not start the bike. Instead the ventilator ran ( ambient temperature 10 degrees C! ) as soon as I made contact.
Fuel pump did not work is what I found after having done desperate tries to start. Startmotor was no issue, battery also in good condition.
So I left the bike and went home by bus and felt a bit weird in my heavy clothing in a warm bus!
After a few weeks I took the time to inspect the bike at work and finally she started after I reinstalled the battery. No ventilator doing overtime, fuel pump running as hell.
At the time I thought it was a wiring problem. On the way back home when I stopped for 5 minutes and shut the bike down the issue was back again : ventilator running although the bike was not overheated, fuel pump was not operating! While blood was running to my head I checked the Motronic unit by taking off the plug a bit, wiggle with it and put it back and oh wonder! Ventilator dead, pump running and she started immediately!
So it seems to be an error in the plug or the contacts. At the moment I do not feel comfortable to ride, I need to be sure the problem is solved.

Any ideas and help from you guys is appreciated!

I found a similar problem for someone with a K75. It does not have the Motronic unit as its 2 valve, but it disappeared when I went to remove the unit so we suspected at contact problem at the plug. From what you say I would take out the unit and clean up the contacts on both the plug and the unit itself with a very fine wet and dry paper used dry. You should be able to get the contacts looking like new ones, shiny.

I also recall that if the sensor registers the engine as overheated, which has the fan running, then it will not start. If cleaning the contact pins does not work check out the temperature sensors. You need to check the manual for the location. This also is a known item. But, since the problem disappeared when you went at the Motronic plug go for that first. When you went at the battery you also would have disturbed the unit.....and again it worked.

Welcome Motorbelg  

Still haven't found the solution? (11 Dec 2014, 17:28)

Hello Wheeldigger, Olaf and all,

The plan is to do what Olaf suggests, clean all contacts of the Motronic. I have already checked the temperature sensor and it gave a normal resistance.
If the old lady starts I plan to do some small trips close by to gain confidence.
If that's not giving any problems then I'll assume that the issue is gone and I will ride my K to work again!
I'll report any progress here.
Thank for your support!