There can be no doubt that Soichiro Honda left a lasting legacy by lending his engineering talents to the company that bears his name. This can be said particularly of motorcycles , and the company outdid itself when it introduced the 1969 CB750. Widely considered the world's first superbike, it combined a then-powerful 67-horsepower, 736cc, inline four-cylinder engine and cutting edge tech for motorcycles at the time like an electric start and front disc brake. It is simply one of the most important motorcycles ever made, and now one of four handmade prototypes is up for auction on eBay Motors According to the seller, Honda had an idea that it had something special with the CB750 and built four preproduction models to be shown off to American media in 1968. Each one was hand-built by Honda technicians from bespoke components, and this blue/green model was photographed by magazines and for promotional material at the time. The seller believes that one of the four prototypes was destroyed, one is in Europe and one is unknown, which means this may be the only chance for collectors to get their hands on one.The bike has prompted quite a bidding war with 97 bids registered as of this writing. With about seven hours left to go in the auction, the top big currently sits at $135,300. At this rate, things could get very exciting at the end. Although to own a prototype for the first super bike, it might be worth it.