have one mounted on a world models sky raider mach II, runs fine except I'm getting air bubbles between the remote needle valve and the carb, none between the tank and valve, any ideas or suggestions before I tear into the valve? I have already replaced the line between the valve and carb, no change

It's either a loose connection on the line or a bad o ring on the needle. Since you've replaced the line it's time to unscrew the needle and get a new o ring.