Help 1974 JDX6 with a KEC 400/22 Pistons???

[ditchbanger1978]

Hello all great site. I got this 74 jdx6c with a KEC 400/22 reed motor and it now needs a piston and I have not seen any for sale. Its got a stock bore 63mm. Everything I have seen is 65mm. The piston is burnt I planed on rebuilding this motor but cant find parts anywhere. This sled only has 350 miles on it and is in overall great shape so I really wanted to save it. I am not sure what caused it to blow up. I think it was the seals but it also had some spark issues.It was very lean on the pto side. Please help I am open to ideas. Thanks Jim