Can I legally remove my name from a loan if the co-signer has possession of the vehicle and refuses to pay?

No.  The dispute is between you and your co-signer, and doesn't affect your obligations to the lender.The lender advanced money based, at least in part, on your credit.  It has done nothing to justify forfeiting that benefit. I assume that when you say "co-signer" you mean on the motorcycle loan, not title.  If so, you can sue your co-signer for failing to make his/her share of the payments, if your agreement was that he/she was to pay part or all of the loan.  Also, depending on how title to the motorcycle is held, you can sue your co-signer for the value of his/her use of the motorcycle and/or to return the motorcycle.