The UK-based workshop JETS Forever has crafted “CROWN JEWEL,” a meticulously executed tribute to a “what if” moment in Yamaha racing history. This is one cool custom Yamaha R5-B cafe racer.
The build is inspired by the legendary Montjuich Class—a specialized endurance racing category from the early 1970s that demanded machines capable of both high-speed tarmac battles and explosive standing-start performance.
Custom Yamaha R5-B Cafe Racer Is the Bike We All Really Want in the Shed
Drawing from California racing folklore and the scrapped “Red Rocket” project, lead builder Tony Taysom and creative director Jeff Duval reimagined a 1971 Yamaha R5-B as a hypothetical factory prototype. The result is a machine that bridges the gap between a track-ready endurance racer and a street-legal 350cc twin, treated with the reverence of a museum-quality restoration.
At its core, the bike features a 348cc air-cooled two-stroke engine that has been fully rebuilt, balanced, and fitted with Amal Concentric MkII carburetors for optimal endurance performance. The chassis utilizes a modified and restored OEM frame finished in a striking black with subtle red metallic flakes, complemented by period-correct Yamaha badging.
While it maintains a vintage aesthetic with its lead-axle forks and 21-inch front/18-inch rear alloy wire wheels, it incorporates modern performance upgrades like Beringer racing brakes and Speedhut competition gauges.
The visual identity is defined by a stunning candy metallic red and pearl white livery with gold leaf pinstriping, perfectly capturing the spirit of a bygone era when Yamaha’s lightweight smokers were first challenging the dominance of larger four-stroke rivals.
Sources: Pipeburn, JETS Forever
