This is for anyone who can help me. I have a GY6 CF250 4 stroke water cooled.It originally had a external reverse gear box on it. But the input shaft for the gear box broke. Now keep in mind it is a 250 not a 150. the 250 has a 23 spline shaft and a 150 has a 19 spline shaft. Mine has a 23 spline inside the tranny. And a 19 outside going into the reverse gear box. And there's the problem. I can not find one to replace it. Now any suggestions on how to replace the shaft and get rid of the gear box all together.