AMA Competition Bulletin MX18101: Clarification of the Limited Class Air Box Rule

TimeTuesday, April 24, 2018 | 3:10 PM

To: AMA Amateur Motocross Competitors

From: AMA Racing

Date: April 20, 2018

Subject: AMA Competition Bulletin MX18101, Clarification of the Limited Class Air Box Rule

The purpose of this Competition Bulletin is to clarify the limited class rules with regard to air boxes. The air box may not be changed or modified. The air box cover is considered part of the air box. 

For reference, the following is from the 2018 AMA Racing rulebook, Section 1.2 Motocross Equipment.

B: 1. To be eligible for a LIMITED CLASS, the following ARE NOT PERMITTED to be changed or modified:

Air Box Front Forks
Air Box Vent Tube Front Fork Caps
Air Filter Screen Intake Spacer
Air Intake Boot Internal Engine Components (blue printing is not allowed)
Axle Lower Triple Clamp
Brake Rotor Size (thickness/diameter) Oil Injection System (only oil may be in system)
Brake Master Cylinder Rear Shock
Carberetor (including any parts with exception to jets) Reed Valve Assembly (any part)
Clutch (any part including clutch cover) Rim Size
Crankshaft Stroke Length Silencer (tip may be modified to accept spark arrestor)
Cylinder Bore Size Subframe
EFI Throttle Body Swingarm
Electronics Transmission (any internal part)
Exahust Control Valve (ECV) Yamaha PW50 Start/Run/Off Switch
Exhaust Pipe (any part) Water Pump Assembly (any part except the cover)
Frame Wheel Hubs

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