They can probably get you with:
Obstruction prohibited
(3) The number plates shall not be obstructed by any device that prevents the entire number plates including the numbers from being accurately photographed using a photo-radar system. 1993, c. 31, s. 2 (5).
or
Rear lamps to illuminate number plate
(19) The lamp on the rear of a motor vehicle or trailer shall be of at least three candela and shall be so placed that it will, at any time from one-half hour before sunset to one-half hour after sunrise and at any other time when, due to insufficient light or unfavourable atmospheric conditions, persons and vehicles on the highway are not clearly discernible at a distance of 150 metres or less, illuminate the numbers on the number plate, or, if provision is made on the number plate or on any attachment furnished or required by the Ministry for affixing the lamp, it shall be affixed in the position or space provided, and the lamp shall face to the rear and reflect on the number plate a white light only. R.S.O. 1990, c. H.8, s. 62 (19).
Your license plate light will face to the side or front, not to the rear as required and whether the lamp is on the rear of your bike is also debatable.
There are other sections they could drag out too.
As others have said, although you are probably guilty and can easily be charged, normally that won't get you the ticket. This one is normally an add-on (or roadside reduction from speeding).