These frame stabilizers for 45”/750 cc W & WR Flatheads replace the seat post units and were already used back in the days to counteract the stresses and strains of racing, as the frames often threatened to break around the rear motor mount area. This relatively light tubular construction with welded ends solves this problem, as the seat post tube is reinforced from the inside. The stabilizer is inserted into the seat post tube and held in place by a flange attached to the top. The tube is fixed from below with a 5/8" screw.

To enable installation, the frame must be drilled out at the bottom and the seat post bushing has to be removed.