Advanced Motorcycle
Technology from Honda
R&D The Honda V45
Engine
More
than power makes the V45 engine better than other street
engines. The objective: a new street bike engine with
improved performance. The technology: the V45 engine. A liquid-cooled,
90-degree V-4 displacing 45 cubic inches (748 cc). The first V-4 engine in a
modern production street hike. Designed by Honda R&D and built for the V45
Magna™ and V45 Sabre™. The bottom line to the V45 is easy to understand: the
best power characteristics in the 750 class. But more than power distinguishes
the V45 engine from its competition. Because the V45 engine is a breakthrough in
motorcycle engine design as well as in performance. The vee configuration
makes the V45 extraordinarily narrow-just 16.3 inches from sidecover to
sidecover. So it can be mounted low in the Magna and Sabre for more responsive
handling and still provide outstanding cornering clearance. It also permits a
low seat height as well.
The 90-degree angle between the V45's cylinders
gives the V45 perfect primary balance, minimizing engine vibration. Link-type
rubber engine mounts eliminate secondary vibrations for even smoother running,
but without sacrificing frame rigidity The four-cylinder layout makes the V45
engine more powerful than a V-twin because it can pump a larger amount of
fuel-air mixture through the engine in a given amount of time. Furthermore, the
four-valve cylinder head with a narrow included valve angle improves combustion
efficiency and permits high rpm operation for even more power.
Thermostatically controlled liquid-cooling narrows the range of the
V45's operating temperatures. And uniform engine temperatures contribute to
outstanding long-term reliability. Even so, the liquid-cooled V45 is lighter
than a comparable air-cooled four-cylinder engine. A unique powertrain design
enables the transverse rotation of The V-4's crankshaft to be efficiently
converted to the longitudinal rotation of the shaft drive system. The rotation
of the crankshaft is simply reversed compared to a conventional engine. So no
extra power robbing crossover shaft is required in the gearbox. The transmission
is further simplified by locating the driveshaft's shock absorber inside the
swing arm.
There are many things that make the V45 engine the strongest in
its class. A 90-degree vee configuration for smooth running, a low center of
gravity and outstanding cornering clearance. A four-cylinder layout with a
four-valve cylinder head for increased power. Transistorized ignition, automatic
cam-chain tensioners and screw-type valve adjusters for easy maintenance. A
hydraulically actuated clutch and simplified powertrain to transmit the engine's
power to the rear wheel efficiently Yet the new V45 is more than just a
powerful engine. It's a better engine, too.