2003 Suzuki LT-Z400 Factory Service Manual, Page 72Get this manual
FREE END GAP AND PISTON RING END GAP the the vernier calipers, and then lit the into the cylinder and rneasure the ring end gap using tile thickness gaugeIf any measurement exceeds the service replace the ring with new one
ITM' 09900-20101: Vernier
Piston end Service Limit: 1st: 5.5 mm 2nd: 9.2 mm
09900-20803: Thickness gauge
Piston ring end Service Limit: 1st: mm 2nd: 0.50 mm