Very rare Cosworth 13.5:1 Piston Kit: 2010-2016 Honda CRF250R Not many of these around anymore. These pistons run phenomenal. For anyone that knows who COSWORTH are….. you know all of their products are of exceptional quality. It’s almost hard to sell this and not be able to stare at on our desk every day. Technically, the compression ratio will vary between the different combustion chambers from the different versions through those years. Mostly non issue. It will fit them all though. Please always check clearances when installing any piston. Includes: -Piston -Rings -DLC Pin -C-Clips