I had the same problem and ive got around it by shortening the rear shock by about 15mm, im running a pitpro 125 frame, fastace bs33ar and an alloy rear swingarm similar to pitpro/dhz type. I cut the top off the shock, removed the left over piece from inside the top and then cleaned up the threads and re-sealed and re-assembled it. My shock now measures 265mm centre to centre.