Make your motorcycle base, delete the area where you want wheels, put a thin layer behind the area the wheels should be, glue those on then add rubber wheels put motor bolts add a rocket if you want, add a area where you can grab, put a grab switch on it, attach it on to the motor bolts then you can color it with your choice of stickers.
You cannot.
use an emitter
you cant
With a scoreboard
Make a really good level
Make a good level
Yes, the motorcycle is not street legal and they did not make many
Because you can make your own levels
Make a good level
Use options to make it a favorite
You just go to create mode and make anything
Hard question, but in my opinion, yes. In ModnationRacers you can make better mods and tracks + it's easier to make karts. But in LittleBigPlanet, you can create whole levels instead of tracks.