Only you know your husband.

Is he feeling like the one you got for your birthday was waste or not good enough? Guys are/can be present sensitive in a weird way.

Do you have a birthday coming up?..LOL.

Back off for now. You know how he feels even if you don't know or understand the reason why. The more you press, the more it sounds like he'll clam up. He knows you want a new bike. If you don't need it right now, just wait. It's added stress between the two of you that neither of you need.

The extreme version is just go buy the bike you want and hope things don't blow up. I don't suggest doing that though.