Hi! 

After long time I bought a project K100RS 1984 and I'll change steering bearings. When I took steering head apart there was only one dust cap (with lower bearing). In some Internet videos they put dust cap also with upper bearing. I can't see this upper dust cap in Realoem. What do you think?? Should I install a dust cap also with upper bearing??

I assume you mean item 9 in the RealOEM diagram? No. If you install an upper dust cap you won't be able to seat the bearings properly without getting stiff steering. I know - one of my bikes arrived with an upper dustcap and it was horrible. Like you, I checked RealOEM and then threw it away.

Somebody else may have the dustcap in?

Thanks for your reply! Yes, number 9 in Realoem. I think I won't install dust cap with upper bearing.

On Airheads from 1970 and steel framed K bikes, the lower triple clamp's metal dust seal is the same, and as you now know, only used at the bottom.