Posted 11.23.20
| 2021 ATVMX PRODUCTION STOCK CLASS CHART | ||
| ITEMS IN QUESTION | Notes | |
| Yes: Allowed to change or modify | No: NOT allowed to change or modify; must remain OEM | |
| BODY AND CONTROLS | ||
| Handlebars | Yes | |
| Hand Guards | Yes | |
| Clutch Lever | Yes | |
| Grips | Yes | |
| Bumper | Yes | |
| Grab Bar | Yes | |
| Steering Stabilizer | Yes | |
| Safety Reflectors | Yes | |
| Clutch Cables | Yes | |
| Plastics | Yes | |
| Seat Covers | Yes | |
| Seat Foam or Pan | Yes | |
| Headlight and Brake Light | Yes | |
| Skid Plates | Yes | |
| Powder Coat / Paint | Yes | |
| Parking Brake | Yes | |
| Handlebar Risers | Yes | |
| Steering Stem | Yes | |
| Steering Flag | No | |
| Bar Clamp | Yes | |
| Foot Pegs | Yes | |
| Heal Guards | Yes | |
| Shift Lever | Yes | |
| Throttle Housing | Yes | Includes switching to twist |
| Decal | Yes | |
| Radiator Shrouds or Louvers | Yes | |
| Add Foam (Mud Inhibitor) | Yes | |
| BRAKES | ||
| Brake Master Cylinder | No | |
| Brake Pads | Yes | |
| Brake Rotors | Yes | |
| Brake Lines | Yes | |
| Pedal / Levers | Yes | |
| Rear Brake Hub | No | |
| ENGINE | ||
| Internal Engine Modification | No | Including engine blue printing and crank balancing; Must use OEM replacement parts |
| Cylinder Bore Replating | Yes | |
| Exhaust | No | Whole or part; May remove emissions pieces |
| Muffler | No | |
| Timing Plugs | Yes | |
| Clutch Plates | Yes | Must maintain OEM shape design and material |
| Clutch Arm | No | |
| ECU | No | Flashing OEM ECU permitted |
| Carburator | No | Jetting permitted |
| Leak Jet | No | |
| Fuel Screw | No | |
| Carb Float Bowl | No | |
| Throttle Body | No | |
| Intake Spacer | No | |
| Reed Valves and Assembly | No | |
| Oil Injection System | No | Must use oil |
| ECV (Exhaust Control Valve) | No | |
| Cherry Bomb (Suz) | No | |
| Clutch Cover | No | |
| Ignition Cover | No | |
| CHASSIS | ||
| Ti Bolts | No | Unless sold on production quad |
| Ceramic Bearings | No | Unless sold on production quad |
| Bearing | Yes | Must maintain OEM shape, design, and material |
| Air Intake Boot | No | |
| Air Box | No | May remove lid |
| Air Box Vent Tubes | Yes | |
| Air Filter | Yes | |
| Air Filter Screen | No | May not remove |
| Oil Cooler | No | |
| Gas Tank Thermal Cover | Yes | |
| Countershaft Cover / Case Saver | Yes | |
| Drain Bolts and Filler Plugs | Yes | cosmetic only |
| Radiator Hoses | Yes | |
| Radiator | No | |
| Radiator Fan | No | |
| Wiring Harness | Yes | |
| ECU Location | Yes | May move |
| Capacitor / Condenser | Yes | May add |
| Solder Fuel Pump Connection | Yes | |
| Breather Box | Yes | May move vent lines |
| Battery | Yes | |
| DRIVE | ||
| Chains | Yes | |
| Sprockets | Yes | |
| Chain Guides | Yes | |
| Chain Rollers/ Sliders | Yes | |
| Sprocket Hub | No | |
| FRAME | ||
| Frame | No | Material may be added for strength |
| Subframe | No | Material may be added for strength |
| Subframe Support Rails | Yes | |
| SUSPENSION | ||
| Internal Modifications | Yes | Respring and revalve only allowed; Compressed and extended length must maintain OEM spec. |
| Shock Springs | Yes | |
| Shock Valving | Yes | |
| A-Arms | No | |
| Swingarm | No | |
| Linkage | No | |
| Bushings | Yes | Must remain same material as OEM |
| WHEELS AND AXLE | ||
| Wheels | Yes | |
| Tires | Yes | |
| Front Hubs | No | |
| Front Spindles | No | |
| Rear Hubs | No | |
| Axle | Yes | |
| REQUIRED | ||
| Kill switch | Yes | |
| Nerfbars | Yes | |