I'm going to trick my friend into thinking that his bike was stolen.
Why are you going to pretend that the bike was stolen?
His bike is so awesome and I want to take it from him.
That sounds like a bad idea. You shouldn't lie about the bike being stolen because you want to keep it.
What's wrong with taking his bike? It was a sick bike.
If you like his bike so much, then you should save up for one of your own. Taking his bike is legal, and it's also grounds for ending your friendship if he finds out about it.