I purchased my new Super 8 150 last week and could not keep the backrest locked in an upright position for riding or refueling. I removed and disassembled the back seat which was easy. I discovered it worked via a cam. The business surfaces did not match up perfectly and were slipping. I used a Dremel to resurface the cam so that they fit together well and voila! I now have a backrest which stays in place when riding . . . or refueling . . . which one has to do too much IMHO. I wish the gas tank was bigger. But other than that I love this bike so far.
