Privateer Racing 115cc bore kit. This is one of the best bangs for the bucks for your TRX90. Kit comes complete with our Privateer Racing head, 25mm Intake valve – 22mm Exhaust Valve, Privateer Racing cam and performance rocker arms, matched high compression piston kit as well as our aluminum high quality 54mm x 69mm cylinder. We have built this kit and taken all of the guess work out of building this kit so that you do not need and cylinder spacers or custom made item to make your motor kit run properly. This piston kit will not run on a stock head without custom machine work, only matched to our Privateer Racing Head. Some material might need to be removed from your motor case to allow the cylinder skirt to engage in the motor case.