Riding Heaven's Highwayson the grand tour
Join Date: Sep 2007
Location: Tehachapi Mtns, Calif.
Bikes: '10 C'Dale Tandem RT2. '07 Trek Tandem T2000, '10 Epic Marathon MTB, '12 Rocky Mountain Element 950 MTB, '95 C'dale R900, "04 Giant DS 2 '07 Kona Jake the Snake, '95 Nishiki Backroads
ct-vt-trekke has it 100% right, it is a self extracting eccentric.
So, since you have both the ""stop nut"" and the allen-head bolt out of the eccentric at the moment, first put the allen bolt back in the eccentric until it lightly seats,, then put back the "stop nut just like it was, then put an allen wrench through the 'stop nut' and turn the allen bolt counter clockwise....it will turn easy for a turn or two, then it will get harder to turn as it butts against the backside of the 'stop nut' for a turn or two until it pushes the wedge piece free on the opposite side of the eccentric.
It is a nice simple setup that works well. Good luck