I just bought me 2 sets of original BMW seals for 2 bikes, sure I got the right ones wich will last another 20 years.

When I replaced my seals 20+ years ago I packed heavy silicone grease between the dust covers and the seals. I change the grease every 1-2 years depending on conditions encountered. Seals can also benefit from the fitting of gaiters, and the occasional cleaning with a Seal Mate. I so far haven't fitted gaiters but if I were riding a lot of gravel roads I probably would.
Regards Martin.

So far a set of gaiters has protected my fork seals for around 75,000 miles. I got them from Motorworks, but don't ask me whether they were OEM or third-party, 'coz ten years on I'm buggered if I can remember!! The gaiters lasted around 65-70,000 miles before splitting to the point where I decided to replace them.

G'day Dan, when I first cleaned up my K75 which has the factory optional 'S' forks, I used 5W oil and the factory spec volume of 280ml for those forks.

The result was that I felt the bike handled well and tracked true over all surfaces including some very poor sealed roads around Dungog in NSW however the front end was very harsh to my way of thinking. I am no suspension guru and do not have racetrack skills but after thinking about this for 20-30,000km I decided that maybe the harshness was caused by the fork rebound not being damped enough. I had never had the forks bottom out so felt the compression was OK.

I changed the fork oil to 7.5W and immediately felt an improvement. I've done another 20,000km at that and am soon to change the oil to 10W to see if that improves the ride even more.

Just my experience.

The standard K100 forks may behave a little differently to my forks as they have longer travel and take 330ml of oil.

Cheers

I'd use original seals because it's a type of job you don't want to do twice. 

But I have to admit I just use automatic transmission fluid for oil, because I've got enough to last for ever.  It's good as far as I can tell,  but I don't go around corners trying to break records,  or anything like that.

I'm aware of folks on another forum using SKF fork seals.  They are reported to have very low stickion (?) but are priced at a high premium.  Has anyone here fitted them to their K-bike?  

Thanks for the replies - I’ve got some genuine seals on the way (motobins - far cheaper then M&W BMW in Brisbane, looks like no OEM sold by Munich in WA)

I might give 10w a go I think.

FWIW: I've always had very good results using Honda SS-8 (10W) in all of my K bikes in the factory recommended amounts.

I used 7 weight  in the recommended amount last year when I did my seals and also packed the dust cap with silicone grease . Big improvement in the feel of the front end when riding on rough road .

Over the years I've played around with oil amounts and weights but I'm now happy running stock.
Regards Martin.