Improved Capped Flywheel + Ring Gear + Gasket for Yamaha YFM 600 Grizzly 1998-2001 | # 4WV-15451-00-00 5GT-85550-00-00Don't Repair. Replace like a pro! New Heavy Duty Flywheel Rotor + Ring Gear + Gasket for Yamaha ATV Introducing our newest Heavy Duty Flywheel Rotor For Yamaha ATV. Anyone who rides or repairs the Yamaha ATV is probably familiar with the flywheel problems common to these models. Most of these vehicles will have at least one flywheel failure in their lifetime so far. Low quality epoxy was used on OEM flywheels to secure the magnets to the rotor body.