This file consist of several object: piston, connecting rod, and crankshaft. Notice that each object has its Pivot Point positioned in specific place (shown in red color). These objects are also positioned in coordinate (0,0,Z) to make bones placement easier.
2. In Command Panel, go to Create>Systems tab. Click Bones button. In IK Chain Assignment rollout, choose SplineIKSolver and activate Assign to Children. Assign to Root will be activated automatically. Then in Left viewport, click three times to create bones. Right click to finish. Make sure you click from bottom to top (1, 2, and 3). In opened window, just click OK. Now, you have SplineIKSolver. Notice that you have bones, spline, and several small boxes (called helpers). These helper are named from Point 01 to Point 03, just like bones. Helper acts like a vertex in spline. .... see the rest of the tutorial at http://www.escalight.com/tutorials/3dsmax-tutorials/piston-engine-animation.html