I just replaced a commercial toilet from a top spud to a back spud. Same dimensions,
1 1/2'' spud. Using the same flush valve with the addition of a 6'' extension pipe curving to the back spud. It works fine, except that it flushes 4 to 5 times the amount of water before it stops. I changed the flush handle and all the parts are working. Can anyone please help.:confused:

Are you talking about a wall mount toilet with a Slone Valve? Top spud washer coming from the flush vale? Back spud washer coming from the rear of the bowl where it connects to the carriage? Your problem is with the flush valve?:What make and model is it? You haven't given me anything to work with here. I need details before I can answer. I'll wait on your reply, Tom