Harley-Davidson filed a new patent showing a variable valve timing system. This is a welcome development for the Milwaukee motorcycle brand following more stringent Euro 5 emission standards that could potentially put their bikes into early obsolescence. For now, loyal Harley-Davidson fans may be assured that classic favorites like the Iron 883 and Forty-Eight could get this new engine tech moving forward.
At first glance, the patent sketches still appear like a conventional air-cooled V-twin engine, typical of a Harley-Davidson. However, a closer look reveals that the engine includes a cleverly placed Variable Valve Timing (VVT) system integrated into it.
The VVT timing system was first Pioneered by Honda way back in 1983 with the CBR400F. It eventually became integrated into a number of Japanese motorcycles throughout the 1990s and early 2000s. It is the first time that a VVT timing system has made its way to a Harley-Davidson V-twin engine, and it’s a welcome development for the American motorcycle brand.
The operation of a VVT is a fairly complex undertaking, more so with a classically styled V-twin engine configuration. The mass of its parts falls under its balance module and the crank is connected to the small gear (#154) which then rotates the gear above it (#158). Behind that larger gear is a smaller toothed sprocket that turns the chain (#178), which spins the balance weight (#86) in the opposite direction to the crankshaft. The VVT unit itself (#98) is connected to the cam gear, which adjusts the timing of both the intake and exhaust valves.
In general, VVT systems are lauded for boosting an engine’s low, mid and top-end power and torque. For Harley-Davidson’s aging engines and motorcycle range, getting them up to speed with the ever-tightening emission standards becomes more difficult and costly to update its internals without sacrificing power. The VVT is one of the simplest ways to improve overall performance even if it is just a bit. Hopefully, this engine tech finds its way on to even more bikes soon. .