The Bearhawk 4-Place (pre-Model B) uses a 1.5” wide leaf spring for tailwheel suspension. The Model B kits come with the round tail spring like the Patrol & LSA. But the spring is thicker (1″ vs 7/8″) when compared to the Patrol or LSA.
When installing the tailwheel start with this spring. There is a large bolt in the front, and a “U” clamp (provided by Bearhawk Aircraft) in the back.
Preparing the Tail Spring
The tailwheel assembly is held to the aft end of the spring assembly with a single bolt. On this aft end, it is necessary that the holes in the springs have an oval shape, as to relieve any scissor action that may occur between the two leafs when the spring flexes. See the drawing to the right and verify that your spring has the correct shape hole. If yours was part of a very early kit, the easiest way to open up the holes is with a rotary tool or die grinder and a small grinding stone or carbide bit, although a large chain saw sharpening file works too. Look down through the two leaves and grind the holes into an oval that is about 1/8” bigger, fore and aft, than the hole was, with the original dimension side to side.
Installing the Spring Clamp
The “U” shaped spring clamp will nest around the spring, but just barely lacks touching the mount that’s welded to the tail post. That’s on purpose, so the AN4 bolts on each side can pull the spring up tight. The gap should be no more than .032” and bolt tension will take that up.
A Note About the Bolts
The bolts in this part of the plane are subject to serious loads in operation, so be sure to check them regularly for proper torque. The only way to visually check the bolt condition is to raise the weight off of the tail and give the assembly a wiggle. If you find that the bolts were loose, replace them, since they will likely have been worn by the movement of the parts. Keep a set of spares on hand. When the weight is on the tail, the bolts will appear to be tight whether they are or not.
Attaching the Tailwheel to the Spring
The “Bob” tailwheel body has thick side plates that are welded to the main attachment plate. Ensure that the tailwheel spring is seating fully on the main attachment plate, and not rubbing on a weld bead. This can be done by applying a radius to the top of the top tail spring. If the tail spring is resting on a weld bead and not making full contact with the main adjustment plate, in service the weld bead will wear down and the assembly will become loose. The steering springs to the rudder horn should have just enough tension that there is no slack in the chains.

Builder Bruce Case drew this nice diagram of Bob’s tailwheel design:
Bearhawk Tailwheel Exploded Diagram