2003 Suzuki LT-Z400 Factory Service Manual, Page 71Get this manual
Measure the diameter the micrometer at 15 mm in) from the skirt end" If the diameter is less than the service the with new one"
09900-20204: Micrometer
Piston diameter Service Limit: 89.880 mm (3.5386
CLEARANCE
Measure the side clearances of the 1st and 2nd the thickness gauge" If any clearance reading exceeds the service limit both the and piston