2005-2008 Honda ATV TRX500FA/FGA Fourtrax, Rubicon Factory Service Manual, Page 424Get this manual
IGNITION SYSTEM The ignition timing is correct if the "F" mark on the flywheel aligns with the index mark on the rear crankcase cover at idleIncrease the engine speed and make sure the "F" mark begins to moveINDEX MARK
"F" MARK Coat new O-ring with oil and install it onto the timing hole capInstall the timing hole cap and tighten it to the specified torqueTORQUE: 10 Nm (1.0 kgfm, lbfft) Install the recoil starter cover (page 2-4)