Kitaco reinforced balanced crankshaft for CRF50 and Monkey is the strongest stock stroke crankshaft on the market. Newly designed H-Rod forged connecting rod offers lighter reciprocating mass while increasing strength. 41.4mm stock length for use with 50cc, 75cc, 88cc, 95cc kits. Must be used with the supplied special oil pump spindle on CRF50 installs.