Yamaha RD250(C) Owner's Manual page 136

b) Slightly loosen the t w o headlight m o u n -
ting nuts and refit the rim to the
headlight body.
N O T E :
Do not tighten the anchor screw yet.
c) Next, adjust vertically by moving the
headlight body. W h e n adjustment is
c o m p l e t e hold the body in place, remove
the rim and tighten the t w o mounting
nuts. Then refit the rim to the headlight
body.