When you think of motocross bikes, the image that likely comes to mind is a rugged, single-cylinder machine, built for the rough terrains and high jumps of the motocross world. But what if I told you that there was a time when Yamaha dared to venture into the unknown and introduced a twin-cylinder motocross bike? Intrigued? Let's dive into the captivating tale of the 1975 Yamaha Twin-Cylinder YZ125.
A Double Take at First Sight
At an initial glance, the 1975 Yamaha Twin-Cylinder YZ125 might seem like any other bike. But a closer look reveals its unique twin-cylinder design, a rarity in the motocross world. While there have been a few twin-cylinder motocross bikes in history, such as the 1980 Gilera Bicylindrical and the Aprilia 450cc four-stroke twin, none have garnered as much attention as Yamaha's creation.
The Birth of the Twin-Cylinder YZ125
This audacious project was spearheaded by Yamaha's Ed Scheidler in late 1974. With a rich history of working with Yamaha, including wrenching for renowned racers like Tim Hart and Broc Glover, Scheidler was the perfect candidate to bring this prototype to life. Starting with a 1975 Yamaha YZ125 monoshock frame and a 1974 Yamaha TA125 road race engine, Scheidler meticulously crafted a new engine cradle and artfully designed the down tubes to accommodate the twin exhaust ports and pipes.
Challenges in Testing
However, pioneering work often comes with its set of challenges. The twin-cylinder engine posed several issues:
Lack of space for an airbox.
A short shift lever that made shifting tricky.
Tall gearing that required a large rear sprocket for optimal performance.
A high redline with minimal bottom-end power.
Absence of a kickstarter or electric starter.
Despite these challenges, the bike showcased impressive speed on straight paths, leaving other bikes in its dust. However, its cornering left much to be desired, often losing the advantage it gained on the straights.
The Legacy of the Twin-Cylinder YZ125
While Scheidler believed in the potential of the project, the limitations of the TA125 powerband and transmission meant that further development would require new components. With no suitable engines or transmissions readily available, the YZ125 twin was eventually shelved, becoming a forgotten relic of motocross history.
However, in 1976, Kelvin Franks embarked on a similar project, crafting a bike using a Franks Honda CR125 frame with a Yamaha TA125 twin engine. Raced by Mike Bell at Irwindale Raceway, the bike showcased a blend of thrill and challenge, echoing the sentiments of the YZ125 twin.
Conclusion
The 1975 Yamaha Twin-Cylinder YZ125 stands as a testament to Yamaha's spirit of innovation and the ever-evolving world of motocross. While it may not have seen the light of day as a production model, its legacy lives on, reminding us of a time when boundaries were pushed, and the impossible was made possible
Source: Motocross Action Mag.