No, in the question's current form it's not on-topic here.
- The answer to "what are the simplifications used in motorcycle road racing video game physics" is
"it depends (on the game)," which is generally too broad, and even if
a specific game were in mind, it'd be off-topic because we don't
answer questions about how specific games implemented specific
features.
- The answer to "are these different from game to game" is
"yes," and yes-or-no questions are generally frowned upon as they are
implicitly too broad (as the implicit follow up is "how" and the answer to that is "it depends").
- The answer to the third bullet point is... you guessed it... "it
depends." It's basically the same as the first bullet point.
A question about modelling the physics of a motorcycle that arose from a problem related to some specific (perhaps ultra-realistic) attempt at simulating those physics would probably be on topic. That is, "I am simulating a motorcycle this way, and it always falls over on corners I think it should be able to take" or something like that.
But I'm not sure that's really at all related to what the OP wants to have answered. I'd suggest they ask off SE, on a place like GDNet.