I appreciate that this has probably been asked and answered on here but I haven't really got the time to search for the info needed and don't know the best place to start looking, so since everyone on here is so nice, friendly and knowledgeable I thought I would just start a new thread and ask.

I need to replace my fork seals as they are leaking and rather badly now (should have done it when I first noticed it really!) and I have got the new seals today but the person at the shop I got them from didn't know which oil and how much I would need for them. So my first question is this, what weight of oil do I need for a K100 and how much is needed for each fork please?

Second question. Does anybody have any tips as to the best and easiest way to do the job?

The best way to go about sourcing info from the forum is to simply type a general phrase or two about your subject into the forum search window.

I typed 'fork oil level' and got this:

https://www.k100-forum.com/t840-changing-the-fork-oil

this

https://www.k100-forum.com/t1439-forks-and-oil

and this

https://www.k100-forum.com/t7962-k100lt-fichtel-sachs-fork-oils-seal-replacement

plus many others.

Having said that, I prefer lighter weight fork oil such as 5W or 7.5W because it allows the fork to react quickly to subtle bumps in the road surface, especially with my bike's retro, harder shorter sprung K75S 'sport' forks. Get a bloody great big drain pan, lay out the tools req'd, have a read of the various threads, block the front of the engine, remove the calipers, front wheel, slide the forks tube down and out, etc., and be very careful on the drain screws when tightening them back up as they strip if you so much as linger on a look at the sweet arse of the passing loverly out on the street, and have a measuring device in CC. Good luck, it's an easy and enjoyable, often overlooked, task.

Thanks for that.

Just picked up some 7.5 oil on the way back from collecting kids from school/college so will likely have a good read of those links tonight and tackle it tomorrow as the weather is meant to be slightly better!

One caution.  There seems to be a bewildering plethora of forks for these bikes, and they all use different amounts of oil.  Then there is one amount for oil change, and another for a complete rebuild, and some bikes use different amounts in each leg.

Make very sure you have the right amounts.

Grizzly,
I found the easiest way of filling the forks is to use an old washing up liquid bottle.

 Clean out the old wu liquid and fill with 360cc (or whatever volume your bike requires) of water, using the nice clean kitchen measuring jug. Then mark the level with a permanent marker. Dry out the bottle.

Now you can retire to the garage and add a piece of plastic tube to the nozzle, making sure that it's a tight fit.

All that's needed then, is to fill with oil to the level marker, re-fit the cap and tube and squirt the oil down into the fork leg. Much less mess than trying to use a funnel and cheaper than buying a syringe.



Paul.

Nice idea.

Cheers Paul.

From what I have found, my bike should be 330cc. Does that sound correct for a bog standard K100?

Edited as I just realised it's 330cc and not 325cc as I typed first.

Good tip Paul!

Yes Grizzly, 330cc for a std K100 and 360cc for a RS, RT, LT. The tolerance being -10cc....according to my 1988 BMW K series repair manual.
I never knew that a standard K100 required less fork oil than the faired models: you learn something new every day here. 

Paul.

I suppose it's down to the lower weight of the bike?

May start another thread but wondering how feasible (if possible at all) it would be to fit a fairing onto my bike? Like the look of the fairing on the LT models and it would also give me more surface at the front for marking my bike up for doing marshalling duties on it.

At last yesterday I got around to sorting my forks out.

Must admit it has made one hell of a difference. Hadn't realised they had got so bad!



Thanks for all the advice on how to do it. I used the suggested squeezy bottle and it worked a treat. Only problem I had at first was how to measure out 330ml as I found the measuring jug had a great big crack in it. Solution - pop to the shop and buy a can of cola and empty that into the bottle, let the bubbles settle and mark the level.



Everything cam apart nice and easy too which was good and the whole job start to finish took me only a couple of hours.

Grizzly wrote:Thanks for all the advice on how to do it. I used the suggested squeezy bottle and it worked a treat. Only problem I had at first was how to measure out 330ml as I found the measuring jug had a great big crack in it. Solution - pop to the shop and buy a can of cola and empty that into the bottle, let the bubbles settle and mark the level.

330mL (33cL at my daughter's place in France). No good here in Oz - most cans are 375mL.


Bill

The cans that count in my opinion are either 440ml or 568ml over here!