can someone explane this to me, its a 1999 honda 400ex
find out the specs
What I like to do is lossen the nut that holds the rocker arm tight against the top of the valve spring, then slide in a feeler gauge that is one size too big and hand tighten the nut, then slide the feeler gauge out and torque the nut down. 9 times out of 10 the gap will be perfect. Then stick in the correct size feeler gauge and if it slides around snugly you know its good
this may help - - -
http://www.atvriders.com/articles/valveadjustment400ex.html