Ok, so it turns out that i can't edit the entityclasses.xml. So it looks like the only way you can get a marker for your minibike is by putting a lock on it, which will stop anyone else from being able to use it. You can then set a password, i'll just choose something like 0000 in case anyone else wants to use it. It looks like they may be bringing out a better way of being able to track your bike, something that can be easily changed, like they currently have on console.