40 CFR 86.419-78 - Engine displacement, motorcycle classes.
(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole cubic centimetre, in accordance with ASTM E 29-67.
(2) For rotary engines, displacement means the maximum volume of a combustion chamber between two rotor tip seals minus the minimum volume of that combustion chamber between those two rotor tip seals times three times the number of rotors.
cc=(max. chamber volume − min. chamber volume) × 3 × no. of rotors
Title 40 published on 2013-07-01
no entries appear in the Federal Register after this date.