2001-2006 Honda TRX 300EX Sportrax 300EX Factory Service Manual, Page 274Get this manual
BRAKE SYSTEM INSPECTION Check the caliper cylinder and pistons for scoring,
scratches or damageMeasure the caliper cvlinder .0SERVICE LIM IT: 4.020 11.3394 in)
Measure the caliper piston 0.0
SERVICE LIM IT: 33.870 mm 11.3335 in l