Often hard to find 17 tooth, 420 pitch front sprocket to fit all years Honda Grom, and CRF50 with mainshafts from 4, 5, and 6 speed close ratio transmissions. Will not work with stock CRF50 mainshafts. Also fits Z50 CT70 NSR50 NSF100 and many more models from Honda. Hardened steel and pre drilled for lighter rotating mass and maximum performance.