I was on the fence between Wiseco and JE for mt new piston and ended up getting the JE 600R piston for my 650L. The one turn off for me was the JE spiro-lock for the wrist pin. I was surprised when I got the JE piston today in the mail and no spiro-lock but a regular / normal retaining pin. Glad to see it but when / why the switch? Damn nice forged piston BTW. I will be honing my cylinder and fitting it tomorrow. Wooo Hoo!!!!