The Yamaha TRX850 is a sports motorcycle with a 10-valve DOHC 849 cc 270° parallel-twin engine. First released in Japan in 1995, a version for the European market was available from 1996 to 2000.
Yamaha TRX850
A TRX with modifications: wavy brake discs, Blue-Spot calipers, braided brake lines & Blue-Ray titanium cans
Balance shafts are used in piston engines to reduce vibration by cancelling out unbalanced dynamic forces. The counter balance shafts have eccentric weights and rotate in opposite direction to each other, which generates a net vertical force.
Balance shaft in Ford Taunus V4 engine.
Lanchester's vertical force balancer. The eccentric masses are labelled "C" and "D".
Valve timing gears on a Ford Taunus V4 engine. The balance shaft runs off the small gear on the left (the large gear is for the camshaft, causing it to rotate at half the speed of the crankshaft).