Should I bring the YZ426F out to @moto_pacific Wednesday night practice again or bring something else? Yamaha used a 5 valve head on the YZ400F, YZ426F and YZ450F through the 2009 model. What are your thoughts on 5 valves versus 4? @redbullmotorsports @redbull @motosportinc @rdrco.inc @bbrmotorsports 🎥: @claireparker_916 🏍️: @mikemoniz50 @mjohnson28 #YZ426 #YZ426F #yamaha