Finally a priceworthy option to Takegawa and Kitaco. Amazing quality and same performance as Takegawas 4v SOHC head. 11:1 compression. Head, race cam, roller rockers, 54mm piston kit etc are included. If you want to tune your Takegawa, Kitaco or Daytona 124cc engine this is the kit for you. You can fit it to the GK4, Monkey 12v, Dax 12v, CRF50 12v, Replica Monkey/Dax as well, but you need a 54mm cylinder (69mm tall) and a 54mm crank.