2002-2006 Yamaha YFR450FAR Service Manual LIT-11616-16-01, Page 161Get this manual
CYLINDER AND PISTON
3.Measure: Ring end gap Out of specification ReplaceNOTE: You cannot measure the end gap on the expander spacer of the oil control ringIf the oil control ring rails show excessive gap, replace all three ringsEnd gap Standard Top ring 2nd ring Oil ring Limit 0.200.40 mm 0.65 mm (0.00790.0157 in) (0.0256 in) 0.400.60 mm 0.95 mm (0.01570.0236 in) (0.0374 in) 0.20.7 mm (0.00790.0276 in)
CHECKING THE PISTON PIN 1.Check: Piston pin Blue discolorationgrooves Replace, then check the lubrication system2.Measure: Piston pin-to-piston clearance Measurement steps: Measure the piston pin outside diameter aIf out of specification, replace the piston pinOutside diameter (piston pin): 19.99120.000 mm (0.78700.7874 in) Limit: 19.971 mm (0.7863 in)