Looking for 24 volt 650 + watt electric motor with belt drive sprocket

I have been looking for a belt driven replacement motor that is at least 650 watts but to no avail. I found several motors that would fit the bill but they all have chain sprockets. My first thought was to buy one of those motors like the currie 24 volt 900 watt motor on monsterscooterparts and attempt to switch out the sprocket on the motor but I am unsure of the feasibility. Can anyone tell me if switching out the chain to belt sprocket is possible or how difficult? I would really like it if someone could point me to a 650 watt motor (or higher) that comes with the belt sprocket.