1992 K75

Decided to service the forks of my recently acquired bike and found some one had been there before me and butchered the shallow headed damper rod Allen screws. Only able to remove them by hammering a suitable size Torx bit into the head. Closer observation showed them to be well recessed in the counter bored hole so bought 2 standard M8x70 cap screws.
The original screws have a head thickness of 5mm, standard screw 8mm.  Bit of trial and error with my grinder I found the head could be reduced to 6,5mm and give me clearance when the wheel spindle is fitted so gained an extra 1,5mm of Allen key engagement.
This may be common knowledge as a fix but thought I would mention it just in case.

This month's "MacGyver Award" winner. Now try to get it next month!  ;-)

Put some anti-seize on the threads when you put it back together.

Bricklayer wrote:This month's "MacGyver Award" winner. Now try to get it next month!  ;-)

Thank you Bricklayer. Never heard of him until now, I'm flattered.

I had a similar problem on an earlier K's lower fork yoke. The heads of the screws seem soft. 
I find these issues and solutions most satisfying.

I encountered a similar problem, with the recess in the bolt head all buggered up. I also ground down a standard cap screw and installed it, but only used it as a temporary fix because the shallow depth resulting from grinding the head down would lead to that bolt socket being stripped later. As the more permanent fix, I ordered the replacement BMW fastener (with the shallow head and pilot recess) and then ordered a hex key with a pilot recess from McMaster-Carr for myself and Two Wheels Better (I had to use his mailing address because the company wouldn't ship to my Alaska address). Here is the part number and description:  4585N16 Hex L-Key with Pilot Recess, 6 mm Size from www.mcmaster.com.  I spent some time looking for those wrenches, and they are hard to come by. McMaster-Carr was the only place I found them.

I cut off the "L" end of the key and use it in a 6mm socket and wrench to get more torque on it.

That's interesting MikeyD. Have never come across that configuration before, a new one on me.

From my experience with flat twin and K's I have usually found that the BMW supplied Allen keys have never felt a snug fit in a BMW cap screw hex where as for example my recent repair with the new ground down head the key was an excellent fit into its female counterpart.

If indeed those damper screws are piloted, the spec for the screw is DIN 6912 and the correct wrench for it is a DIN 6911.

I did a search on DIN 6911 and several sources came up. 

Here's one:

https://fullerfasteners.com/products/din-6911-hexagon-key-with-guide-point/

A suggestion: whenever dealing with these shallow head screws(on the fork leg or lower triple clamp) for the first time it is a good idea to use a brand new key and heat in case someone put Loctite on it.

When you put the screw back, make sure you put anti-seize on the threads.

suggestion 2 Apply heat to the KEY not the screwhead, allow a short time to cool 1 minute or so this allows the heat to penetrate deep into the screw maximising the chance of full releasement of the screw.

I would be careful about heating the key.  The good ones are usually hardened tool steel and heating them will draw the hardness and make it easier to round off the key's corners making it easier to strip out the screw's head. 

Those corners are where the torque is transmitted.  That's why you want to use a new key when going after these shallow head screws the first time.  The heat is to soften any possible Loctite that might have been used before you.

Thanks, Point-Seven-Five. It's always good to have more sources for tools!

Too many years of experience in stripping fork legs makes me head for one particular tool every single time: an impact driver with a good hex key in it. Hit it a couple of times in the tighten direction first to help break any corrosion (or loctite!) and then really wallop it to unscrew it.