Inside the 2016 Honda® RC213V-S Engine

The V-4 engine utilizes a 360-degree crank phase angle, which leads to more favorable exhaust pulses and increased charge efficiency for better power. Additionally, the irregular interval of combustion helps improve traction performance. The 90-degree angle eliminates the need for a balancer and the associated mechanical losses, as well as making the engine more compact.

The major changes from the RC213V are the use of traditional valve springs in the S as opposed to pneumatics, and a conventional transmission instead of the seamless transmission. These changes were made based on servicing requirements and the necessity that the RC213V-S be serviced in "a realistic maintenance environment."

A V-4 engine also has a shorter crankshaft than an inline-four, reducing engine width, in turn increasing potential lean angle and reducing frontal area for better aerodynamics. Friction losses in a V-4 engine are less than in an inline-four, as fewer crank journals are required (three vs. five).

Titanium connecting rods are used for high rigidity and low weight. Bridge-type pistons are used for weight reduction and for compliance with emissions regulations; the RC213V-S has three rings on each piston; the top ring, second ring and an oil ring.

A straight, short intake port is used, which reduces port volume for improved throttle response. The valves are set at a narrow angle, limiting the surface area of the combustion chamber to increase combustion efficiency. Valves are lightweight titanium alloy, actuated using finger followers.

The gear drive system for the camshafts improves reliability in the high rpm range and reduces friction. A total of 10 gears are used. On the MotoGP bike, backlash is adjusted by selecting from a multiple number of gears; the RC213V-S uses an eccentric adjustment mechanism with coaxial cam gears, allowing adjustment without the need to replace gears.

Mounting the water pump on the cylinder head has several benefits, including: increases lean angle; eliminates the need for reduction gears in the pump drive (as the camshaft spins slower than the crankshaft); and places the radiator and water pump closer together, reducing water pipe length and the amount of cooling water required.

The RC213V and RC213V-S both use a dry-sump oiling system with a scavenge pump to maintain negative pressure inside the crankcase and reduce pumping loss

The S-model uses a cassette-style transmission, but not the seamless design of the RC213V. The transmission parts are made from "wholly machined nickel-chrome molybdenum steel.

The RC213V-S uses the same assist & slipper dry clutch as the RC213V, with hydraulic actuation. A centrifugal governor system enables starting the engine from the rear wheel using an engine starting unit or by a push start

Both the RC213V and RC213V-S use connecting seals between the throttle bodies and the cylinder head, with the throttle bodies rubber mounted. This helps to reduce the intake port length

Dual fuel injectors per cylinder are used, with the top injectors mounted to the throttle body. The airbox is made from CFRP, with aluminum fuel delivery pipes, injector stays and air funnels