I'm going to buy a motorcycle without my boyfriend's consent
Why are you buying one without his consent?
Because I want it.
I understand wanting to buy something for yourself, but making a purchase without discussing it with a partner is always a way to hurt the relationship. It's always best to have the conversation first.
I really don't care what he thinks about it honestly.
Doing something so large behind your boyfriends back might ruin the relationship, even if you don't care about what he thinks.