Motorcycle Disc Brake Rotor (Motorco Harley-Davidson compatible)

This item is a used motorcycle disc brake rotor, likely for the front wheel given its size and general appearance, though it could also be a rear rotor. It is constructed from metal, likely steel, and features a circular design with a central mounting hub. The rotor's surface shows distinct concentric wear patterns from repeated contact with brake pads, indicating prior use. Numerous small, circular holes are drilled along the outer edge of the braking surface, which serve to dissipate heat and improve wet braking performance. Closer to the center, the rotor has several larger, elongated slots or cutouts, which contribute to weight reduction and heat management. The central hub has five bolt holes for attachment to the motorcycle wheel. There are visible manufacturing details stamped on the central section: 'MOTORCO G.B.' and below it 'S.W. 2.9 (MIN THK) 44135-00 F.B.' followed by 'DOT'. The '44135-00' likely corresponds to a part number, and 'MIN THK 2.9' indicates the minimum recommended thickness for safe operation, currently showing more than 2.9mm. The 'DOT' marking signifies compliance with Department of Transportation standards. The metal exhibits typical signs of age and use, including some surface discoloration, minor scratches, and light rust patina in areas not actively worn by braking. There is a handwritten marking in red on the braking surface that appears to say 'Good' or 'Poop', suggesting a quick assessment of its condition by a previous owner or mechanic. The overall craftsmanship appears robust and functional, consistent with a mass-produced automotive component designed for durability and performance. Estimated age is from the early 2000s based on the '44135-00' part number format often seen in Harley-Davidson or similar era motorcycle components.

Upon visual examination of this motorcycle disc brake rotor, I assess its condition as fair to good, consistent with a used automotive part. The concentric wear patterns, surface discoloration, and light rust patina are typical for a component of its age and use. The visible stamping 'MOTORCO G.B.', 'S.W. 2.9 (MIN THK) 44135-00 F.B.', and 'DOT' strongly suggest authenticity as an OEM or high-quality aftermarket part, likely Harley-Davidson compatible, given the part number format. The 'MIN THK 2.9' indication is crucial, and based on the description, the rotor appears to be above this minimum, which is a positive functional attribute. The handwritten 'Good' or 'Poop' mark is an amusing anecdotal sign of prior quick assessment. In terms of market conditions, used motorcycle disc brake rotors, particularly for common models like Harley-Davidson, are readily available. This item falls into a category with moderate demand but also significant supply from both new aftermarket options and used parts. Rarity is low; this is a common wear item. Factors significantly impacting value include its used condition, the minor surface deterioration (rust, discoloration), and the general availability of such parts. Its age (estimated early 2000s) also places it in a less desirable category compared to newer, more technologically advanced rotors. It is important to note that this authenticity verification is limited to visual examination of the images. For full authentication and a definitive assessment of its structural integrity and metallurgy, an in-person examination would be necessary to check for warping, runout, and precise thickness measurements. Provenance documentation, such as service records or original purchase receipts, would also add to its verified history.