2005-2006 Honda ATV TRX500FE/FM/TM FourTrax Foreman Factory Service Manual, Page 341Get this manual
REAR DRIVING MECHANISM Replace the pinion gear shim with thicker one if the contact pattern is too high, toward the faceTOO HIGH: PINION GEAR SHIM
Drive side Replace the pinion gear shim with thinner one if the contact pattern is too low, toward the flankThe pattern will shift about 0.51.0 mm (0.02 0.04 in) when the thickness of the shim is changed by 0.12 mm (0.005 in)Pinion gear shims: A: 1.64 mm (0.065 in) B: 1.70 mm (0.067 in) C: 1.76 mm (0.069 in) D: 1.82 mm (0.072 in) E: 1.88 mm (0.074 in) F: 1.94 mm (0.076 in) G: 2.00 mm (0.079 in) H: 2.06 mm (0.081 in) I: 2.12 mm (0.083 in) J: 2.18 mm (0.086 in) TOO LOW: