O.E. style replacement 16T front sprocket for 79 Yamaha RD400F Daytona, 77-78 Yamaha XS400D/2E, 78-79 Yamaha XS400E/F/2F, 80-81 Yamaha XS400G/H Heritage, 80-81 Yamaha XS400S G/H Maxim & 82 Yamaha XS400S J Seca. If you wish to order a different size sprocket to change your gearing, feel free to give us a call to order the size you desire.