after the lack of OS support with these engines im going to say stay away from these engines. all they could say without even opening up the engine was refer to page 17 "no warranty..."

too many of these engines are having conrod problems. unfortunately for mine when the conrod went it took out a piece from the bottom of the piston then went thru the the liner.

dude for the little money more go for the mugen ninja r01. ive heard many great stories about these and ive seen them run at our track, they are really fast and seam reliable to finish races.

i will be throwing out this vz-r and getting a mugen ninja.