This flywheel has an adjustable hub making timing adjustments on the fly relatively simple. Loosen the 6 hub bolts, rotate the flywheel on the hub, then tighten the bolts. Each adjustment line on the flywheel represents 2 degrees. Using a timing wheel and finding where the coil triggers with a timing light will determine the actual timing setting. Further adjustment can be obtained with an advance timing key or no key at all. Hardware included to align the coil with the magnet on this flywheel and spacers included to move the blower housing out (same hardware that's included with the non adjustable billet flywheel). The starter cup needs to be modified if you plan to keep using the recoil starter. Air gap on the coil should be at least .030". Use 54 lbs-ft of torque for the flywheel nut. There is no torque specification for the hub bolts. Tighten them until the lock washers bottom out and then turn slightly more. Adjustable flywheels are for the racer looking for easier tuning options at the track or on the dyno.