2005-2009 Honda TRX400EX/TRX400X Service Manual, Page 302Get this manual
IGNITION SYSTEM
IGNITION TIMING
Start the engine and warm it up to operating temperatureStop the engine and remove the timing hole cap from the left crankcase cover
Reao' rhe manufacrurer's insrructions lor riming Ilghr and rachomerer opera-
Connect the timing light and tachometer, Start the engine, let it idle [1,400 rpm (min'!)] and check the igni tion timing