Honda CRF450X 2020 Owner's Manual & Competition Handbook page 127

Brake Pad Wear
Brake pad wear depends on the severity of usage
and track conditions. (Generally, the pads will
wear faster with wet and dirty track conditions.)
Inspect the brake pads at each regular maintenance
interval (pages 33, 34).
Front Brake Pads
Inspect the brake pads (1) through the front wheel
to determine the brake pad wear. If either brake
pad is worn anywhere to a thickness of 0.04 in (1.0
mm), both brake pads must be replaced.
(3)
minimum
thickness indicator
(2)
(1)
replace
0.04 in (1.0 mm)
wear indicator
grooves
(1) brake pads (3) brake disc
(2) front brake caliper
Rear Brake Pads
Inspect the brake pads (1) from the rear side of the
caliper to determine the brake pad wear. If either
brake pad is worn anywhere to a thickness of 0.04
in (1.0 mm), both brake pads must be replaced.
(2)
0.04 in
(1.0 mm)
(3)
(1) brake pads
(2) rear brake caliper
(1)
Other Inspections
Check that the front brake lever and rear brake
pedal assemblies are positioned properly
(page 116) and the securing bolts are tight.
Make sure there are no fluid leaks. Check for
deterioration or cracks in the hoses and fittings.
minimum
thickness indicator
0.04 in
(1.0 mm)
(1)
replace
(3) brake disc
Brakes
119
Servicing Your Honda