Yamaha’s Crossplane Engine – A Real Simple Explanation
In 2009 Yamaha threw a rock into the calm Japanese waters with a 1000cc superbike the world did not recognize. The all-new crossplane crankshaft R1 threw conventional thinking out the window and tackled a new and innovative approach to engine performance.
The production model 2009 R1 was a trickle down in development after years of refinement in the MotoGP world championship, where a crossplane engine fueled Valentino Rossi to multiple world titles from 2004 through 2010 aboard the Yamaha YZR-M1.
Not usually known for radical or out-of-the-ordinary tendencies (more like consistency and constant (albeit slow) progress towards the future), the Japanese engineers at Yamaha quite literally threw a wrench in conventional Japanese engine design, which has become quite stale in the most modern era of motorcycles.
When so many manufacturers create 4-cylinder engines with differences measured in single millimeters, the public was left to wonder when someone would step up and innovate.
In 2009 Yamaha said enough of the “same old” inline 4 engine configuration and mass produced an engine based upon its newly developed MotoGP technology, an engine with an irregular firing order. Amazingly, the engine with the exhaust note of a V4 arrived to instant critical acclaim. This idea was (and still is) revolutionary.
But more than the rave reviews and all the bantering about improved traction and crossplane cranks…
What Does Crossplane Really Mean?
Included below is a video straight from Yamaha which does a great job explaining what is really so great about the R1’s crossplane engine.
To put it simply, the R1’s crossplane engine negates the effect of unwanted intertial torque in “conventional” 4-cylinder engines. You see, when a rider turns the throttle, we ask for a certain amount of torque (combustion torque, the torque provided by the firing of the engine/pistons).
However, what we also receive when we twist that throttle is an unwanted side-effect, intertial torque, which is quite different from what we asked for. Inertial torque is the product of the masses within the rotating engine internals that speed up and slow down within their 360 degree cycle. What this does is create quicker and slower spots within each crankshaft rotation of a typical 4-cylinder engine.
In summation, the crossplane R1 takes the combustion torque you ask for and matches it up with overall torque output, negating the effect of inertial torque between the cylinders, offering a smoother power delivery and only giving you the power you ask for, nothing more and nothing less.