Trail Bikes Roller Rocker Head V2 Kit For 88cc & 108cc for Fits: Honda Z50 (1988-1999 ONLY) Honda XR50 - CRF50 Honda XR70 - CRF70 Honda CT70 (1991-1994 ONLY) Features: -Roller Rocker Arms -28.5mm with 5mm valve stem intake valve -23.5mm with 5mm valve stem exhaust valve -23mm Exhaust port -Matching High Compression Piston -Head kits include all hardware -52mm piston with rings - pin - & clips. -High performance race camshaft (for Race Head only) -Head gasket kit. -Race fuel not needed will run better with that but will run on premium fuel