Horse power isn't everything this is because of "energy Induction" setup which gives it a way better power band and long enough to GULP complete gears... GTO lack Streamed power band. gto is a rotry valve engine , it has killer top end power band ( it gives peak performance at higher revs ) where as energy induction has greater pick up , yamaha's are lighter hence they are faster.
rx block is of total alumunium ( the outer sides , where as kawasaki is heavy as hell and of iron caste