I have done this a couple of years ago and I have had to do it again today.
The R1100 series suffers from a weak gearbox mount at the rear end, where the tubular frame fits to it. That is why we have to benefit from the Touratech hard parts.

If you have not already done it, or perhaps you are thinking you ride an RT just on the street, it will fail sooner or later.

A couple of years ago when I first had this problem, a local welding shop fixed it pretty nicely for me. The damage was for the R/H side mount, the upper side of the mount just snapped.

It must have happened sometime between 2015 and now, because in 2015 was the last time I took the gearbox out from the bike, to change all it’s seals…

So what the welder did was to put a sort of coal like material, ~8mm thick, over that existing thread, and start welding over it, filling it.

Can’t really see in the pics but the coal is still in there. Now, I just need to machine that surface flat on the mill, break the coal out and re-thread the M10 hole with a tap that’s designed for blind holes.

I just thought I’d share this with you so that you know that it can be welded and repaired, but I would have it done by someone that knows what they’re doing.

I managed to thread the hole, pretty easy, M10 taps #1 2 and 3.

Then countersunk the hole so that the screw gets in easily

The end of the weld was filed to a flat finish, level with the lower side which was untouched by the weld.
I was then able to lower the frame and put the bolts in…