What is the difference between a motorcycle pushrod engine and a chain-driven engine?
2 Answers
The differences between a motorcycle pushrod engine and a chain-driven engine are as follows: 1. Different valve train transmission methods: The main difference between a pushrod engine and a chain-driven engine lies in the power transmission method of the valve train mechanism. One uses pushrods for transmission, while the other uses a chain. 2. Different performance under specific conditions: The pushrod engine has a simpler structure and relatively more reliable performance. However, pushrod engines perform relatively poorly at high RPMs, and their power output tends to favor low-speed conditions, excelling in acceleration from a standstill and climbing performance, with stronger wear resistance. On the other hand, due to the continuous nature of chain transmission and the lighter mechanical load of the chain itself, chain-driven engines exhibit better noise and vibration performance at relatively higher RPMs, making them more suited for power output calibration at high RPMs.
When I first started riding motorcycles, I didn’t understand the difference between these two engine types either. It wasn’t until I disassembled a few engines that I figured it out. The pushrod engine uses metal rods to open the valves, with a simple structure like an old tank—it’s particularly powerful at low RPMs, handling cargo or climbing hills without breaking a sweat. But at high speeds, the vibration feels like a massage chair cranked up to maximum. The chain-driven engine, on the other hand, mounts the camshaft on the cylinder head and rotates it via a chain, resembling the mechanism of a precision watch. This makes it smooth and quiet at high RPMs, much more comfortable for long rides. The most obvious difference between the two is the sound: pushrod engines produce a clanking metal impact noise, while chain-driven engines emit a smooth humming sound. Nowadays, mid-to-high-end motorcycles mostly use chain-driven engines—after all, no one wants their hands to go numb from vibration after just three hours of riding.
