I have an older rcgf 20cc rear carb engine and I need a new reed valve assembly (b 2021) and they are no longer available. The screw that holds the reed in place has been slipping and allowing the reed to move out of place and has a bad effect on running. I thought about flipping the body over but there is a raised area that only fits in the engine one way. I called a supplier about possibly using the newer version that has two reeds but he did not feel it would work. The motor is a good one and I am trying to find a solution if anyone has any ideas.