Although Canada and Australia allow 250 two-strokes in the same class with 250 four-stokes, they don’t allow Mitch Payton to go anywhere near the cylinders.
For the 2015 CMRC Rockstar Energy Drink MX Nationals, the following amended rules will apply to 250 two-stroke motorcycles in order to be eligible for competition:
(1) The bike must remain in stock form from the intake manifold to the exhaust port, and all engine parts between those two points. All engine parts (ie. cylinder, cylinder head, piston, rings, rod, etc.) must be OEM for that year model.
(2) Intake manifold is defined from the rubber boot clamps to the carburetor. No porting or headwork allowed.
(3) There are no restrictions on pipes or mufflers other than the fact that they must meet the sound rules.
(4) CMRC will be conducting random engine checks throughout the series. CMRC will have a cylinder, cylinder head and piston from each manufacturer for comparison. Any bikes found to be modified will be excluded from the results of the day’s competition.
(5) Additionally, a rider may not switch from a two-stroke to a four-stroke or visa-versa. The type of machine on which a rider begins the series is to be used to the completion (ie. Start on a two-stroke, finish on a two-stroke).
These rules are similar to ones instituted in Australia two months ago—except for the crackpot rule that the rider can’t choose what bike to ride.