Hi, Inge,
Thanks for the part number. If Jimmyk is reading this, he can (maybe) order one from his dealer. The funny thing is, if I check the ETK of one of the larger dealers here in the USA as well as the REALOEM site and click on K75RT, then "steering", the ETK shows the part, but there is no #26, part number, description nor price listed. If I ask for the part number you provided, however, the parts view contains the "locking bolt" and it is in the description (along with the USA price, of $9.42). It's funny, but 30 years ago, I lived and worked in Europe. Both my late wife and I had bikes ('81 R100RT and '81 R65, USA models) without the throttle stop screws. Since we knew they might be difficult to buy in the USA, we bought a supply while in Germany. I think they were around DM4 each (then, a little less than $2.00). And they are now $9.42!