The Yamaha pistons stopped using the turbo and threw oil through the crank ventilation.
In the Vmax part there is an article that show the new pistons and they are nice !
Dynoman performance from Texas advised to use JE pistons and a set of Carrillo rods.
Also a Cometic steel headgasket is used and a Dyna 3000 ignitionbox for the retard function for the turbo.
Less compression means more air to be compressed and that means more fuel = more horsepower!
Read more: New engine interior