In my K bike previous owner has done teflon coating on some parts including the rims. Well it is otherwise OK but when I changed tyres first time they were really hard to put on because of the striction of surface. Well now I sandpapered the rear rim (teflon off) and it was OK when putting a new (used) tyre on it but... It leaks air from several points round the rim.

So what should I do? Sand it with finer paper? Sand it and then paint it?

the paint fills the gaps well tennox ....but it will need time to cure properly ...so it doesn't lift during the tyre fitting process

many a tyre fitter will use some form of soap along the tyre bead during fitting , witch forms a good seal as it dries along the bead

I have recently got to a used wheel and noticed all the rubber detritus left on the rim after several changes ( by me and the tyre fitter ) with new tyres ...I found that acetone cleans most of this crap off the rim really well ....and that is important for a good seal

hope that helps before you attack it with some form of abrasive

One of the rims on my Kawasaki has that problem after some idiot got to it with out using his brain and put a deep score across the sealing surface. I used to put some 3 bond on the mark and the tyre would get rid of what was not needed as it came up onto the bead and left enough there to seal the gap.  It worked well with the next 12-15 tyres.

Thanks guys. Maybe I just sand it some more and then clean it well. Maybe even paint after that. It is stil good 5 months before the winter ends.

I've used XTRA Seal Bead Sealer on my ATV's with good results. Don't know about your application but you may want to give this or the like a try. It does a good job of filling in the inevitable small gouges where the bead and rim meet.

Thanks Kyle. I would not even think anything like that myself. Only problem now is how to find similar product from Finland. 

Any business that fits and sells tyres would have some sort of sealing goo.

RicK G wrote:Any business that fits and sells tyres would have some sort of sealing goo.

It seems that they don't use those chemicals here in Finland. Asked from 2 different places - never heard.. I think I just paint the inside edges of the rim and if it does not help I just put a inner tube (checked that from dictionary) inside the tyre.

On this page you find the material safety data sheet for a bead sealer....in Finnish.

Using the company home page, you maybe can find out if it's available somewhere
close to you........I even don't wanna try reading it..........kippis.

Inge.. Don't even know how you do this.. Thanks. I will check it out. Kippis!

(Will buy you beers if we ever meet)

I was told many years ago NOT to fit tubes on tubeless tyres, excessive heat generation(??)

Rickmeister wrote:I was told many years ago NOT to fit tubes on tubeless tyres, excessive heat generation(??)

Yes, when the tyre it is not tube designed, the heat will made it blow and its not a pleasant experience
Best regards and happy new year
JAP

Well I did little research and did not find it to be completely wrong to put inner tube to tubeless tyre.

http://www.avonmotorsport.com/resource-centre/tube-fitment

http://www.motorcyclenews.com/new-rider/2010/october/oct0710-tubes-and-tubeless-tyres-/

Must check my rear tyre inside if I have to install inner tube. Hope not.

There is no problem with placing a tube of the correct size inside of a motorbike tyre marked 'tubeless'. BMW's new RnineT (and many, many other models) has tyres clearly marked tubeless on it but with tubes fitted due to the lack of a seal with the traditionally located spokes on the wheels, unlike the GS wheels with a sealed rim and 'cross spokes'. Your K bike's wheels can accept a quality tube with no dramas.

My mate who owns a little tyreshop tries to sand and paint the rim for me. It also has a small dent on it and we talked about the material of the rim since it seems so light. I always thought that it is aluminum, mate even said might be magnesium, but am I right - did some research - that 86 K100 rims really are cast iron? If it is, he might be able to straighten it too.

Tenox wrote:, but am I right - did some research - that 86 K100 rims really are cast iron?

If it have been cast iron, it would be a very heavy bastard.......

It is a lot of companies which are specialized in straighten light alloy wheels,
I'm shure you find them in Finland too.

http://www.shopbmwmotorsportonline.com/p/BMW_1986_K100RS/CAST-IRON-RIM-SILVER-REAR-3-00X17-A/42767326/36312311149.html

What are these then?

And straightenin is not an issue anyway. Rim does not shake, even without balance weights. Not even at 200km/h.

But it is aluminum then?

Tenox wrote:http://www.shopbmwmotorsportonline.com/p/BMW_1986_K100RS/CAST-IRON-RIM-SILVER-REAR-3-00X17-A/42767326/36312311149.html

What are these then?

That is an example how things can go wrong when the parts catalogue is
auto translated from german to english.
Have a close look on a online parts catalogue, and you will find a lot of
strange things and names.

The wheels is made of a aluminium alloy.

I found that small dents can be very easily fixed in BMW rims, they are very soft compared to the Japanese stuff.
A piece of soft wood and a 16oz hammer will do the job.

Inge K. wrote:That is an example how things can go wrong when the parts catalogue is
auto translated from german to english.
Have a close look on a online parts catalogue, and you will find a lot of
strange things and names.

The wheels is made of a aluminium alloy.

Thanks.

If you do a google a search "BMW K100 aluminum rims" or "BMW K100 cast iron rims" you will also get interesting results...

Rim is OK. Sanded and painted + dent fixed. Keeps the air inside again.

marvellous outcome

good to hear

cheers !!