No modification is required to use this kit
what the internet says
Increased power and performance for your Yamaha Viking 700
Wake up your Yamaha 350 with a proven combo: Hot Cams Stage 1 (4017-1) for crisp throttle and broader powerband
37F-11412-00-0 573M06600 2XJ-11111-00-00
Polaris Trail Blazer 250 Cylinder Namura Piston Gasket Top End Motor Rebuild Kit YZ450F No modification is required toNA 50000K, 810806, 536M07200, BR8ES, 3087049, 3085541, 3083769, 3083617, 3089277, 3070171, 3070156, 3086757, 3084439, 3084292, 3084033, 3084017, 3084016, 3084015, 3083768, 3083733, 3083676, 3083540, 3082510193564123305, 71420580806, NA 50000R, NA 50000T, NA 50000F, 09 503 1 Revitalize your Polaris 250 with this complete top end rebuild kit. This premium kit has everything you need for a fresh new start, including a new 72mm cylinder and Namura Top End