The 1975 Honda CB750 model, known as the CB750K5, featured a two-up seat design. The seat was typically a long, padded seat that could accommodate both the rider and a passenger. It had a relatively flat shape with a slight rise towards the rear, providing a comfortable seating position for extended rides.
The seat upholstery and design can vary depending on the specific trim or optional accessories installed on the motorcycle. However, the stock seat for the 1975 CB750K5 was typically a single-piece seat with a textured or smooth vinyl cover in a color that matched the overall design of the bike.
It's worth noting that over the years, owners may have replaced the original seat with custom or aftermarket options, so variations in seat design and materials are possible. If you are looking for specific information or are considering replacing the seat on your 1975 Honda CB750, it's recommended to consult with Honda motorcycle specialists, vintage motorcycle restoration experts, or refer to resources dedicated to classic Honda motorcycles for accurate details and options.