Honda RS150R 2019 Owner's Manual page 20

Instruments
Display Check
When the ignition switch is turned on, all the mode and digital segments will show,
and the tachometer segment progress to maximum scale and then disappear.
If any part of these displays does not come on when it should, have your dealer check
for problems.
16
Tachometer
NOTICE
Do not operate the engine in
the tachometer red zone.
Excessive engine speed can
adversely affect engine life.
Tachometer red zone
(excessive engine rpm range)