Introduced in 1976, the Yamaha XS400 emerged at a time when major manufacturers were predicting the end of the two-stroke era and turning their attention back to the development of four-stroke road bikes. The mid-sized XS was designed more as a reliable workhorse than a sporty machine, competing with models like the Kawasaki KZ400, the Suzuki GS400, and the Honda 400 Hawk.
The air-cooled twin offered 45 hp of power and was faster than most of the competition. It wasn’t bad at all, but the small 400cc four-stroke wouldn’t leave any road rider thrilled.
Roman Juriš, from Slovakia, acquired this ’84 XS400 as the foundation for a comprehensive build.
Most importantly, Roman wanted to test a new front suspension concept he has been developing, a Progressive Upside Down Fork (PUSDF) set designed to minimize movement during braking – a system he is patenting. There are three patent applications:
1. Progressiveness – for example, for a 120mm wheel suspension travel, there is a 60mm rise in the fork.
2. When the spring, the front wheel axle is pushed forward, thus eliminating the shortening of the wheelbase.
3. Separation of the spring force and braking force – the motorcycle does not sink during braking.
Roman built the entire frame from scratch and the XS now has a shortened YZF125 swingarm, supermoto wheels, custom fairing with a beautiful paint job, and a unique front suspension setup:
Discover this model with innovative and unique mechanics.
