520 Motorcycle Front Sprocket For GasGas 125EC EC125R 125 EC Racing 2003-2015 Engine Parts Fit For Gasgas 125EC EC125R 125 EC Racing 2003-2015 motorcycles; drive shaft spline; fits standard 520 drive chain Direct bolt on mounting design; aligns shaft tooth position; no extra during chain drive assembly Smooth polished tooth surface; reduces chain friction loss; maintains stable power output during offroad racing riding hardness structure; supports frequent speed rotation; slows surface abrasion over long mileage Standard inner spline tooth dimension; size matching; keeps tight connection with front drive shaft