this is what he bought, it says 260 but he is heavier then that and can ride it, I know it's a walmart bike, but it would start the process of losing the weight and getting you to the point you could ride a standard bike, the other advantage is it wouldn't be as hard on your bad arm, since you wouldn't be trying to balance. With all the smart people on here, someone might even be able to tell you what parts it would need to convert to a multi speed
http://www.walmart.com/ip/Schwinn-Me...icycle/5679542