The Yamaha liquid-cooled, DOHC, 4-valve, in-line 2-cylinder engine, developed based on the "Crossplane Concept" that delivers tenacious torque in the practical range, is used in many models across genres, starting with the road sport "MT-07", followed by the sports heritage "XSR700", adventure model "Tenere 700", crossover Tracer 7 (overseas model), and the supersport YZF-R7, and has been installed in many models across genres. This engine, also known as the "CP2" after the Crossplane Concept 2-cylinder, is not only responsible for Yamaha's middle class, but is also a benchmark for today's two-cylinder engines in terms of perfection.
Written by: Hiroyasu Ogawa Photo by: Yuko Koizumi
Compact design in pursuit of lightness
Equipped with mounting mounts for the rear shock unit, the CP2 is designed to be lightweight and compact not only for the engine itself, but also for the entire body of the vehicle.
MT-07, introduced in 2014, was developed to meet stricter emission and noise regulations, and its engine was newly designed. The engine was designed with the concept of "incorporating elements that make driving enjoyable, since ease of handling alone makes driving boring," and was designed to provide both ease of handling and linear acceleration with easy throttle opening and closing at any rpm range. The in-line two-cylinder layout was presumably decided upon in response to the various requirements for environmental performance, sporting performance, and convenience, and the 270-degree crankshaft is a major feature of the CP2 so developed.
The 360-degree crank used in the T-MAX530 is an evenly spaced combustion system in which the left and right pistons move up and down at the same time, which produces stable torque from low rpm, but also tends to increase vibration and makes it difficult to rotate to high rpm. The 180-degree crank used in the YZF-R25 has the left and right pistons in opposite positions to cancel out each other's vibration, but the up-and-down motion of the left and right pistons separately tends to produce an accidental vibration that causes the engine to oscillate. Combustion timing is extreme, and torque at low speeds tends to drop.
The 270-degree crankshaft was adopted for this purpose. It is exactly like adding a 180-degree crank and a 360-degree crank and dividing by two. The combustion interval is not as extreme as that of a 180-degree crank, and it provides smoother rotational rise than a 360-degree crank. However, vibration does occur, although not as much as with a 360-degree crank.
In fact, Yamaha introduced the TRX850 and TDM850 in 1995, the first production models to use a 270-degree crank. These 2-cylinder engines were equipped with a dual-axis balancer to reduce vibration, but the CP2 used a single-axis balancer. Thanks in part to advances in analysis technology, this engine is calculated to produce vibration but also to feel comfortable. The use of a single-axis balancer was also intended to make the engine more compact and lightweight.
The CP2's crankcase is die-cast and thin-walled to reduce weight while providing strength to support the crankshaft, balance shaft, and transmission. In addition, the water pump and oil pump are coaxially mounted to achieve both compactness and light weight. The upper crankcase is integrated with the cylinder to reduce weight. The starter motor and battery have also been downsized by incorporating a decompression function to reduce compression when starting the engine, and the vehicle balance has been improved by thoroughly reducing weight. The combination of these characteristics and the lightweight chassis make for easy handling at low rpm and linear acceleration up to the mid- to high-rpm range.
The water pump, located under the crankcase, is coaxial with the oil pump to achieve compactness.
A rear shock mounting mount is provided at the rear of the crankcase. The starter motor has also been downsized for total weight reduction.
The engine of the Sport Heritage XSR700 is also a CP2, which, thanks to its compact design, contributes to a slimmer chassis.
The crankcase is also more compact, and the width of the body around the step is slimmer, contributing to improved footing.
Check the footing of XSR700 equipped with CP2
I checked the footing on an XSR700 model equipped with CP2. The rider was 172 cm tall, the seat height was 835 mm, and the handlebar position seemed a little far away.
The width of the motorcycle is slim, and both feet can be worn flat to the soles of the feet. The handlebars are wide, but the upper body can be in a relaxed, upright position.
The rider is 156 cm tall and says, "The lightweight body makes it easy to support me even when standing on my tiptoes, so I don't feel insecure."
The seat in the seating position and the width of the chassis are slim, making it easy to slip in and out. The handlebars are wide and easy to maneuver."
Fat low-speed torque, easy to ride in the city
The compact, light motorcycle-class chassis is easy to maneuver, and the low-mid RPM torque, which is heavily used in urban areas, is fat and convenient.
The XSR700 weighs 188 kg, which is light for a middle-class 600 to 800 cc motorcycle, and its slim chassis makes it easy to get on and off the ground. The handlebar width is wide at 740mm, but the large handlebar angle allows for good turning performance and easy maneuverability in urban areas. The upper body is aligned with the handlebars, making it easy to assume an upright, relaxed posture, and the eye level is higher, providing a good view.
The CP2 has plenty of torque at low rpm, and there is no fear of stalling when starting off or in traffic. It also responds well to throttle operation, and it has sufficient acceleration power even at around 3,000 rpm. Even when the rpm range is maintained, there is no unpleasant vibration from the CP2, and the vehicle's stability increases, allowing it to move with the flow of traffic with a sense of ease. The combination of nimble handling and stable machine behavior also makes it easy to ride, and a wide range of riders should find it easy to handle.
The mid to high RPMs transform the driving experience! You can enjoy a sporty ride!
The CP2 is smooth and responsive up to high rpm, and the XSR700's lightweight chassis also makes for a sporty ride.
Even when shifting up to 5th~6th gear at 3000 rpm, the motorcycle body accelerates quickly when the throttle is opened. At this engine speed range, the driver can enjoy relaxed cruising and feel comfortable both as a daily transport and as a touring companion.
On the contrary, the XSR700's performance suddenly becomes sporty when the rpms are increased above 4,000 in each gear, and the CP2's throaty, 2-cylinder exhaust note is accompanied by an increasing sense of throbbing, and it delivers an instant kick of acceleration in response to throttle operation. Thanks in part to the lightweight chassis, the driver can enjoy nimble machine control simply by opening and closing the throttle. This characteristic, which combines easy handling in the low rpm range and sportiness in the mid-to-high rpm range, is a characteristic of the Crossplane Concept.
On the other hand, the author used to own a TRX850, so he sometimes felt that the XSR700's mid-to-high RPM exhaust note was a bit lacking in excitement. However, the exhaust gas and noise regulations have become much stricter now than they were when the TRX850 was sold new. Since the introduction of the CP2, more and more middle-class 2-cylinder engines have adopted the 270-degree crankshaft, which is due to rival manufacturers' recognition of the CP2's total degree of perfection. This is the best proof that rival manufacturers recognize the CP2's high level of total perfection. If you are looking for a middle-class engine that is not only easy to handle but also fun to ride, a model equipped with CP2 is recommended.
Main specifications of the 2023 Yamaha XSR700
Overall length x width x height: 2075 x 820 x 1130 mm
Wheelbase: 1405mm
Vehicle weight: 188 kg
Engine: Liquid-cooled 4-stroke DOHC 4-valve inline 2-cylinder 688cc
Maximum output: 54 kW (73 PS)/8750rpm
Maximum torque: 67N-m(6.8kgf-m)/6500rpm
Fuel tank capacity: 13L
Transmission: 6-speed return
Brakes: F = double disc, R = disc
Tire: F=120/70-17, R=180/55-17
Price: approx. 381,833 PHP
Original Source [ Webike JP Website ]
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