Bf wants me to co-sign a motorcycle?

so I JUST received my approval for a credit card in the mail today. Not even the credit card it's self. I literally just called him and told him and the first thing he says is "Your going to help me get a bike." since he uses my car to get to work. I've never had one before, and last year leased a Toyota Yaris with my mother as the co-signer. From what I remember when she co-signed for me they scanned her credit. If they do this to me will my credit apr go up? I don't know anything about this but he wants to do it as soon as I get my card. am I going to have to pay some fee or something? what goes into this esp. since I JUST got my first card at 17.99% with a $3k limit. I'm 22 he's 23 with every licence possible he's a driver. What's your opinion? He has the money to buy it almost in full, gets paid well (Manager at a 4star hotel) and is getting a $6k bike from Suzuki.