Technician did mine. I didn't see the process, but I think you pop that little rubber plug on top, loosen the two bolts on the side and reach down inside with an Allen. Not sure if that's right though. He adjusted the front and rear derailer cables too. Bike has never run better. Pretty sure that solved my hands off headshake ( aka. Tank Slapper) . issue too. Battery might be moving slightly vertically on road bumps possibly causing scuff marks. Not sure yet.