As an indication, locally in Australia they cost about AUD$125 each injector. I'd keep an eye on ebay and/or find the part number of the exact injector you're after and search for that.
Going from 440 to 600cc isn't much of a jump. Maybe using a 4bar fuel pressure might help things instead of trying to get new injectors?
Going from 440 to 600cc isn't much of a jump. Maybe using a 4bar fuel pressure might help things instead of trying to get new injectors?