There are many things you could do, but would never choose to do them because you know the consequences. You're asking a question here when it's obvious you simply don't know its consequences.
Assuming you'd survive your first contact with a yakuza member when you raised this idea, you might even get as far as discussing where you'd need to live, how much work you'd be expected to take on, etc., etc. But eventually you'd reach the point in your plans where you'd actually have to do something for them. And this is where it's like jumping from a plane without a parachute- everything might go well for a short time, but it's that sudden collision with reality that would kill you. You'd either be put on a job that would cross a rival gang (you're dead) or made to do something that would make you a police target (you're on trial, in jail, and then dead).
The yakuza don't see themselves as an equal opportunity employer. You don't want to consider this seriously any further unless you have a death wish.