Backwards and counterclockwise are fuzzy terms. If you look at an engine that is running counterclockwise from one side, it will be running clockwise when viewed from the other side.
The direction of rotation of an engine depends on what kind of gearing is in the gearbox. If there is a single gearset the engine will run "backwards" and if there is a double gearset (or no gears) the engine will run forward.
As long as he bike goes forwards it makes no difference.
And yes, like the other thread says, a two stroke can easily run backwards. Years ago there was a little bubble car called a Messerschmidt (sp?) , yes the same maker as the German airplanes in WW2. They mada a little three wheeled car with a Sach two stroke engine in it. The engine had an electric starter and two sets of points in the engine. To back up, the engine was shutoff, a switch was thrown reversing the starter and using the second set of points and the engine would start and run in reverse. Four speeds backwards. Pretty neat but must have been scary.