First of all you need to remove the oneway or check valves, if you run a check valve then you need something to regulate the fuel pressure, also a clunk for each engine would work much better, my Laser V twin has two carbs and Laser recommends a clunk for each cylinder. The way you're set up now with the check valves you have too much tank pressure when you reduce the throttle setting. If you use the Perrys you can get away with one clunk and a tee and no tank pressure.