Honda CB Unicorn 160 Owner's Manual page 70

If the drive chain requires adjustment, the
procedure is as follows:
1. Place the vehicle on its center stand
with the transmission in neutral and the
ignition switch off.
2. Loosen the rear axle nut (1)
3. Loosen the drive chain lock nuts (2).
4. Turn both adjusting nuts (3) an equal
number of turns until the correct
drive chain slack is obtained. Turn the
adjusting nuts clockwise to tighten the
chain, or counterclockwise to provide
more slack.
Align the chain adjuster index marks (4)
with the rear edge (5) of the adjusting
slots on both sides of the swingarm.If
the drive chain slack is excessive when
the rear axle is moved to the furthest
limit of adjustment, the drive chain is
worn and must be replaced.
5. Tighten the rear axle nut to:
88 N·m (8.9 kgf·m, 65 lbf·ft)
64
(3)
(2)
(1)
(5)
(4)
(1) Rear axle nut
(2) Drive chain lock nuts
(3) Drive chain adjusting nuts
(4) Index marks
(5) Rear edge of adjusting slot
(3)
(5)
(4)
(2)