2006 Honda TRX680 Rincon Factory Service Manual, Page 460Get this manual
FRONT DRIVING MECHANISM If the backlash is excessive, replace the ring gear left side shim with thinner oneIf the backlash is too small, replace the ring gear left side shim with thicker oneThe backlash is changed by about 0.06 mm (0.002 in) when the thickness of the shim is changed by 0.10 mm (0.004 in)NOTE: Twenty-three different thickness shims are available from the thinnest (0.50 mm) shim to the thickest (1.60 mm) shim in increments of 0.05 mmRing gear shims: A: (thinnest): 0.50 mm (0.020 in) K: (standard): 1.00 mm (0.039 in) W: (thickest): 1.60 mm (0.063 in) Change the right side shim an equal thickness and opposite amount of what the left side shim was changed; If the left shim was replaced with 0.10 mm (0.004 in) thicker shim, replace the right shim with one that is 0.10 mm (0.004 in) thinnerJ