I'm installing a gx160 in a cat 400x and my questions are I bought a stage one kit from OldMiniBikes and I'm not sure about installing the advanced timing key as I've heard the gx160 was already advanced and dunno if I should use the 140 emulsion tube in it or stay stock and I am installing #18 valve springs in it also I'm not tryin to make a hot rod just goin for a decent pavement pounder.