If you look closely - there are small "ears" that stick out
on the inner covers.
You use this special tool (Noot had an original H-D one)
and lift up the cover, remove clip, and the ears
fit in notches to hold up the covers, so you
can adjust your tappets !
Then you pop the clips in (with square holes)
and undo the ears and the spring tension holds
the covers - and seals in the engine oil.