Dude, why are you still saying this stuff? CMVSS are FEDERAL safety standards, which are primarily directed at manufacturers for the production, development and importation of vehicles/etc. Transport Canada Inspectors enforce it. Municipal and provincial police enforce PROVINCIAL standards, which are the HTA and related regulations. In those PROVINCIAL standards, including the safety inspection regulation, there is zero mention of rear turn signal metrics. In fact, signal lights are not even required on a motorcycle in ON as per ON legislation and regulations.
Again, CMVSS has no bearing on provincial and municipal police enforcement, so it is irrelevant. Checking out the provincial legislation and regulations, there are a lot of grey areas. Plate illumination by white light is needed, but reflectors are nebulous since the language used of "prescribed reflectors" is not further defined in any ON regulations or legislation, and the mudguard requirement is vague. For example, I'd argue that a plate mounted at the rear below an undertail is a mudguard as defined and described by the ON legislation and regulations for motorcycles.
I have an undertail that is legal per the ON HTA act and regulations. However OP, as per your question, even if it is technically legal, law enforcment can pull you over and/or hassle you for such things if they want. They can even charge you and force you to go to court if you want to fight it.
Prescribe:
verb (used with object), prescribed, prescribing.
1. To lay down, in writing or otherwise, as a rule or a course of action to be followed; appoint, ordain, or enjoin.
LIGHTING
6. (1)
Prescribed lamps and reflectors shall be inspected and tested and,
(a) each circuit shall light the filaments of all lamps on the circuit when the appropriate switch is in the “ON” position, and each indicator lamp shall indicate correctly;
(b) the operation of any lighting circuit shall not interfere with the operation of any other circuit;
(c)
each lens and reflex reflector shall be correctly installed and shall not be discoloured or missing in whole or in part;
(d)
each lamp and reflector shall be securely mounted on the vehicle and none shall be missing;
(e) the turn signal lamps and the flasher unit shall operate properly;
(f) the brake light shall operate when the appropriate control is actuated;
.... continues on about headlamps and more ....
The Lighting requirement IS PRESCRIBED in the CMVSS requirements. It's pretty clear, and believe me, the MTO enforment officers don't believe in the 'grey area' because there really isn't one; only a lack of understanding with the language used in the HTA
BODY WORK
1. (1) The motorcycle shall have,
(a) where they were originally installed, securely mounted fenders, mudguards and operative footrests;
The first three lines of Schedule 6 .... Pretty clear again. Your plate is not, nor will it ever be, a mudguard.
FTR, I'm not saying I agree with the requirements; just clarifying