19 Apr 2012 ID: 34896
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CRF250L Press Pack

CRF250L Press Pack

Contents:

1 Introduction

2 Model overview

3 Key features

4 Technical specifications

 

1. Introduction

 

The essence of what makes a true dual-purpose motorcycle has long been in Honda’s DNA. In the late 1970s the XL250S was launched, a bike providing genuine on-road usability with excellent off-road performance. The entire XL range that followed became legendary, and proved that bolting an economical and easy-to-use single-cylinder four-stroke engine into a competent chassis, created a bike that was useful, versatile and, as riders the world over found, fun.

 

Exhaustive discussions within Honda R&D took place about the creation of a brand new dual-purpose machine. The company’s long history – in off-road competition and dual-purpose machinery – was a useful touchstone when development of the bike first began, and inspired the team that worked on it from the outset.

 

Looking to the needs of customers came first. While some riders insist upon competition-level off-road performance, many others value ease of use, practicality and convenience. For weekday, urban use they wanted a tough, practical bike with cutting-edge off-road style. But, come the weekend, it needed to provide a ticket to ride, wherever they wanted to go, on or off-road.

 

Honda’s new dual-purpose platform was always viewed by its development engineers with global perspective, as a bike for the whole world. It not only needed a powerful and frugal engine, its chassis also had to have a broad and capable range. The bike was to be affordable, offering high quality and outstanding value for money, with low overall running costs a priority.

 

Perhaps most important, and a driving force for the engineers working exhaustively to deliver such a multi-faceted motorcycle, was to produce something that could connect many people to Honda, and help them realise their dreams in a way that only a motorcycle can.

 

The CRF250L is that motorcycle.

 

2. Model Overview

 

The CRF250L is a dual-purpose motorcycle. Its dimensions, ergonomics, low weight, long-travel 43mm Showa USD forks and Pro-link rear suspension make it equally at home on city streets or country trails. The single-cylinder engine provides useful power and torque across a wide rev range, with excellent fuel economy. The crisp styling takes cues from the legendary CRF competition range, and, as expected from Honda,both build quality and engineering standard is high.

 

The key phrase used throughout CRF250L development was: “…to make ‘On’ (daily life) more convenient and ‘Off’ (weekends) more enjoyable!”

 

3. Key Features

 

3.1 Engine

 

The CRF250L’s lightweight and compact liquid-cooled single-cylinder 249cc DOHC engine produces smooth and consistent torque at low rpm, aiding rear wheel traction and rider feel. Equally, the short stroke (76x55mm) engine’s high rpm performance is excellent; throughout its rev range and provides well-balanced and very usable power delivery.

 

To create a tractable engine across such a broad rev range, much research and development effort went into the intake and exhaust system. The ideal internal dimensions were found for the throttle body and exhaust pipe, both in terms of diameter and length. A new design of viscous air filter and large 5.7L air box has been employed to maximize airflow.

 

The CRF250L engine team came up with a new and extremely compact roller/rocker arm design for the low-friction valve train. This in turn allowed the use of a smaller cylinder head. An iridium spark plug, along with precise metering of fuel from the PGM-FI injection system, further enhances combustion efficiency and improves environmental credentials.

 

Reducing internal frictional losses, the CRF250L engine uses an offset cylinderwhile the piston itself incorporates a special surface material, plus a molybdenum coating. The oil pump features an internal relief structure that prevents aeration of relieved oil.

 

A first for Honda in a single-cylinder off-road engine is the crank journal. It employs a half-split, press-fit metal bearing while the crank bearing uses a cast-iron bush. The net result of this new design reduces weight and makes for a smoother engine; it strengthens the rigidity of the case housing and minimizes the internal diameter change due to thermal expansion. A primary balance shaft further reduces vibration. The new six-speed gearbox and clutch were designed in conjunction and strengthened to cope with the extra stress riding off-road can produce.

 

The cooling system uses a 10.7 kW heat-release radiator, sited on the left of the bike, protected with a polypropylene grill baffled to improve airflow. A thin guide-ring cooling fan is used to maintain even temperatures at low speeds, either in congested traffic or tricky off-road situations.

 

To deal with Euro III emissions regulations an O2 Lambda sensor works in conjunction with a secondary air injection system. The catalyzer is sited inside the tapered exhaust muffler.

 

3.2 Chassis

 

With the versatility demanded of the CRF250L from the outset, a brand new frame evolved to house the new engine. Constructed from steel, the twin oval-section main spars and semi-double cradle provide the strength needed for off-road riding. The slim, round-section steel bolt-on sub-frame supports two adults plus a 5kg load. Guards are situated above the rider’s foot pegs to protect the frame from boot scuffs.

 

A wheelbase of 1,445mm is matched to a 27.6°’ rake with 113mm trail, giving excellent stability and agility.

 

The 43mm Showa inverted fork is incredibly rigid, with performance perfectly honed throughout its 250mm stroke for use over a wide range of terrain and speeds. Pro-Link rear suspension features a 240mm axle stroke; the Showa shock absorber is a single tube design with 40mm diameter cylinder. The tapered aluminium swingarm incorporates a monoblock casting; a method that allows for production of intricate shapes. It provides the correct rigidity balance while ensuring strength, and reducing un-sprung mass. Extruded aluminium is used for the chain adjustment collar.

 

The front brake uses a single 256mm disc gripped by a two-piston caliper, the rear, a 220mm disc with single-piston caliper. Braking has been tuned to offer excellent feel with a high level of controllability. The lightweight discs feature a wave design – taken directly from the CRF250R/CRF450R – with exceptional self-cleaning abilities in adverse conditions.

 

Lightweight aluminium rims further reduce un-sprung mass. The directly attached spoke pattern layout is taken from the CRF250R/CRF450R and benefits from extreme rigidity. Block pattern enduro-style tyres (front: 3.00-21 51P, rear: 120/80-18 62P) provide traction in a wide range of riding situations. The 21 inch front wheel and 18 inch rear increase stability on rough terrain and allow the fitment of more off-road specific tyres if required.

 

3.3 Equipment/Styling

 

The CRF250L’s digital instrument cluster contains a fuel meter, with built-in clock and twin trip functions. The headlight visor provides visual CRF-inspired styling, protects the instruments and houses an H4 60W/55 bulb.

 

Overall styling of the CRF250L owes much to the elements of the competition CRF-R range, incorporating principles of mass centralization and triangular proportion. Ergonomic considerations were also a key factor, as the bike is required to perform, handle well, and be comfortable in a wide variety of conditions. The braced handlebar provides an upright and relaxed riding position, with plenty of leverage for bike control, and a 45° turning angle either side give a tight turning circle which is useful for dealing with urban traffic or tight trails.

 

The slim fuel tank holds 7.7L, and combined with the comfortable, flat seat offers maximum control and choice of riding position. A compact, lockable toolbox is sited at the base of the rear fender.

 

4. Technical Specifications

 

CRF250L - Specification

Engine

Engine Type

liquid-cooled 4-stroke DOHC single cylinder

Engine Displacement

250cc

Compression Ratio

10.7

Max. Power Output

17.0/8500 kW/rpm (95/1/EC)

Max. Torque

22.0/7000 Nm/min (95/1/EC)

Fuel consumption

32.1km/L (90.4mpg)* (WMTC modeClass3-1) Honda in-house measurement

Oil capacity

1.8L

Ignition

Full-transistor battery ignition

Ignition timing

10° (idling)

Rev limit

10500 (rpm)

Starter

Self-starter

Carburation

Programmed fuel injection system (PGM-FI)

Idle speed

1450±100 (rpm)

Bore & Stroke

76.0×55.0 mm

Battery Capacity

12V 6Ah (10HR)

ACG Output

0.34 kW/5,000 rpm

Spark plug type

SIMR8A9 (NGK)

Throttle bore

36mm

 

 

Transmission

 

 

Clutch

Wet multiplate with coil springs

Final Drive

Chain

Primary reduction

2.807

Gear ratios

2.857

Gearbox / transmission type

Constant mesh 6-speed return

 

 

Chassis

 

 

Frame type

Semi-double cradle

Caster Angle

27.6°

Trail

113mm

Turning radius

2.3m

 

 

Dimensions and Weight

 

 

Kerb Weight

144kg

Maximum allowable weight/load carrying

159kg

Fuel Capacity

7.7L

Length x Width x Height

2.195×0.815×1.195 m

Wheelbase

1.445m

Seat Height

0.875m

Ground Clearance

0.255m

Wheels, Suspension and Brakes

 

 

Brakes Front

Hydraulic disk (256-mm brake disc/2-piston caliper)

Wheels Front

Wire Spoke (Rim size : 21 X 1.60)

Tyres Front

3.00-21 51P

Brakes Rear

Hydraulic disk (220-mm brake disc/1-piston caliper)

Wheels Rear

Wire Spoke (Rim size : 18 X 2.15)

Tyres Rear

120/80-18 62P

Suspension Front

Telescopic (Inverted) 43mm diameter slide pipe

Front wheel travel

250mm

Suspension Rear

Swing arm (Pro-link suspension system) 40mm diameter cylinder

Rear wheel travel

240mm

 

 

 

All specifications are provisional and subject to change without notice.

*Please note that the figures provided are results obtained by Honda under standardised testing conditions prescribed by WMTC. Tests are conducted on a rolling road using a standard version of the vehicle with only one rider and no additional optional equipment. Actual fuel consumption may vary depending on how you ride, how you maintain your vehicle, weather, road conditions, tyre pressure, installation of accessories, cargo, rider and passenger weight, and other factors.

 

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