Kawasaki KX250F - 2011 Information Manual

Kawasaki
Brand
Kawasaki
Model
KX250F - 2011
Category
Motorcycles
Type
Information Manual

This manual is also suitable for

2011 MODEL INFORMATION
MODEL
NAME
KX250F
MARKETING
CODE
KX250Y
INDEX
2011MY KX250F MODEL INFORMATION PAGE 2
OVERVIEW - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - P.3
KEY FEATURES - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - P.4
POWERFUL, HIGH-REVVING FUEL-INJECTED ENGINE - - - - - - - - - - - - - - - - - - - - - - - - P.4
HIGH-SPEED CHASSIS WITH FACTORY-STYLE COMPONENTS & TUNING - - - - - - - - - - P.11
ADDITIONAL FEATURES - - - - - - - - - - - - - - - - - - - - - - - - - - - - - P.18
COLOURS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - P.19
SPECIFICATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - P.20
OVERVIEW
2011MY KX250F MODEL INFORMATION PAGE 3
Fi AND FACTORY TUNING KEEPS EXPERT RIDERS
AT THE FRONT
The KX250F base package provides an excellent platform for race-experienced riders to
win in the top classes.
The design of the highly rigid aluminium frame, suspension components and settings,
focused on ensuring control is maintained during high-speed riding – especially in straight
lines – to enable experienced racers to ride to their maximum potential and to deliver
holeshot-winning performance. The later is a key factor that can mean the difference
between running up front and winning, or getting stuck mid-pack. Chassis geometry and
the high-revving 4-stroke engine’s wide powerband were designed to maximise rear
wheel traction and the combination is a proven race-winner, with multiple UK and
European wins in addition to AMA Supercross Lites and Motocross Lites championships
to its credit.
To ensure the Lime Green racers continue to run at the front, Kawasaki engineers have
made a number of engine and chassis changes to further increase the KX250F’s winning
potential.
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 4
POWERFUL, HIGH-REVVING FUEL-INJECTED
ENGINE
Tuned to best suit race-experienced riders, the 249 cm3 liquid-cooled, 4-stroke single’s
wide powerband focuses on high-rpm performance and extends way into the over-rev.
Already featuring race-inspired tuning and parts like the high-performance piston with
bridged-box bottom (a mass-production first when introduced on the 2010 KX250F), the
2011 engine receives fuel injection and a number of changes for even more power,
stronger low-mid range torque (most noticeable when riding through the whoops, landing
jumps and coming out of tight turns, it allows riders to shift less often, reducing fatigue
and enabling quicker lap times throughout the moto), more accurate shifting and a quieter
exhaust note.
Factory-racer engine tuning
High-performance piston, features the
same design used on our factory
racers and contributes to improved
performance at all rpm, A short skirt,
reinforced external ribs and the
industry’s only mass-production use
of a bridged-box bottom, featuring
fully flush internal bracing, result in a
lighter, stronger piston.
*
A new piston crown, revised to suit chamfering of the squish area, offers increased
high-rpm and over-rev performance.
*
Intake camshaft with revised sprocket/shaft arrangement retards intake valve timing
1˚, to suit the new fuel-injected engine.
Open 10MY:41˚ BTDC 11MY:40˚ BTDC
*
A new spark plug protrudes 1.4 mm deeper into the combustion chamber, improving
combustion efficiency.
*
Intake ducting has about 10% greater volume, resulting in improved response
(especially in the ultra-low rpm range).
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 5
The revised intake ducting and new deep-protrusion spark plug not only offset the
drop in low-mid torque that comes from a change to fuel injection, performance is
actually improved in this range.
*
Revised final reduction ratio offers improved engine feel. The shorter gearing
(13/48T >> 13/50T) further accentuates the increased low-end torque.
*
Cylinder height reduced (36.5 mm >> 36.3 mm) to suit the new piston and higher
compression ratio: now 13.5:1 (previously 13.2:1).
*
Exhaust pipe is longer (480 mm >> 510 mm) to suit new engine characteristics.*
Battery-less fuel injection system
Designed specifically for motocrossers, the fuel injection system incorporates a small
lightweight ECU and operates without a battery to further eliminate unnecessary weight.
And, of course, fuel injection eliminates the familiar need to adjust engine settings to suit
track and climate conditions.
Ensuring quick starting without a battery was a prime directive when developing this
fuel injection system. Using only electricity generated by the kick starter, the engine
can be started with only three rotations of the crankshaft. The system delivers
electricity in the following order:
1) ECU, 2) fuel pump, 3) injector. With a warm engine, starting can be accomplished
in a single kick.
*
The compact, lightweight ECU,
located just in front of the steering
head (behind the number plate), was
designed specifically for motocross
use. To help cope with the shocks
and vibrations of motocross riding, the
fuel pump relay is built in to the ECU.
*
A 43 mm throttle body makes use of a
progressive throttle link to deliver
airflow in much the same way as
would an FCR carburettor. Using two
linked shafts, the throttle body opens
more quickly after the 3/8 open
position, delivering sharp response
and excellent power feeling.
*
Lightweight throttle body is approximately half the weight of an FCR carburettor – a
weight saving of about 600 g.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 6
To ensure the high-rpm engine’s
demand for a high flow of gas in a
short period is met, the KX250F’s
injector features larger holes than that
used on the KX450F. A fine atomising
injector with 4 holes disperses spray
particles with a droplet size of 120
μm. Fuel flow is about 20% greater
than on the KX450F.
*
The newly designed fuel pump,
located in the fuel tank, is a
lightweight aluminium construction.
(Fuel tank capacity is now 7.2 litres.)
*
To ensure a stable fuel supply during vigorous motocross riding, the fuel pump
features a rubber fuel filter cover that wraps around the inlet port and acts as a fuel
trap. A fuel return hose from the pressure regulator ensures there is always fuel in
the fuel trap.
*
Factory KX Fi Calibration Kit (optional accessory)
The KX Fi Calibration Kit is the same kit used by Kawasaki’s works teams and Team
Green dealers in Europe and the U.S. The kit enables Team Green dealers, Kawasaki
race teams and expert riders to adjust engine characteristics (by rewriting actual data
maps) to suit their preference, record riding data, and analyse their riding data to further
fine-tune their settings.
The KX Fi Calibration Kit contains KX
Racing software, an ECU controller,
mounting brackets and damper,
harness and USB cable. In addition to
the kit, a PC and 12 V battery are
required.
*
While the kit is designed to satisfy racers and expert riders, it is designed to be
simple to use:
- the ECU controller mounts behind the number plate for easy access
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 7
- accessing the ECU is accomplished simply by connecting to a PC via the ECU
controller using a USB cable (no additional switches are necessary)
- setting adjustments can be prepared in advance on a PC, or done when
connected to the ECU
- the kit’s user-interface is simple to understand and easy to use
*
The KX Fi Calibration Kit contains seven preset settings that can be quickly and
easily used to adjust the ECU to suit track conditions. The provided settings are
shown below.
Richer fuel setting: fuelling 5% richer than stock
Leaner fuel setting: fuelling 5% leaner than stock
Advanced ignition setting: ignition advanced 3˚ from stock
Retarded ignition setting: ignition retarded 3˚ from stock
Hard riding surface setting: ignition retarded, fuelling richer
Soft riding surface setting: ignition retarded, fuelling leaner
Beginner setting: engine power suppressed: ignition retarded, fuelling richer
*
For more advanced setting optimisation, the ECU maps for volume of fuel injected
(via the Fi adjustment window) and ignition timing (via the IG adjustment window)
can be adjusted for given throttle position and rpm.
Base settings are shown as a flat graph (left). Settings can be increased or
decreased
from the base according to rider preference (right).
*
Multiple display options are available. Click [3D Graph] or [2D Graph] of the [3D/2D]
to select the 3 or 2-dimensional display. When you use the [3D Graph], select
[Surface Display] or [Frame Display] of the [3D Graph Type] to select the display
type.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 8
Both click-and-drag (using the graph window) and numerical editing (using the map
sheet) are possible.
*
When connected to the ECU, the KX Fi Calibration Kit can be used to display the
status of a running engine. Information can be displayed in numeric form using the
Data Monitor, or in visual form using the various display options offered by the Data
Meter.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 9
The KX Fi Calibration Kit can also be
used as a data logger, recording up to
six hours of data depending on the
number of parameters (engine rpm,
angle of throttle opening, etc) being
recorded. After riding, the riding data
can be viewed using the [Analyze]
window. Parameters
to be recorded and displayed can be
selected independently.
*
The logged data can lined up with the course layout to check actual riding, enabling
more efficient Fi settings to be determined. It also enables before-and-after
comparisons and comparisons between riders.
*
For more detailed information on use and functions of the Fi Calibration Kit, please refer
to the KX Fi Calibration Kit Instruction Manual.
Less mis-shifts
A longer ratchet lever causes the ratchet to turn a greater amount with each shift
(53o >> 60o), reducing the chance of mis-shift.
*
A lighter ratchet lever return spring ensures that shift lever weight feel remains the
same.
*
Reduced noise
On European models, pinched
cut-outs in the silencer chambers
direct exhaust gases into the
glass-wool packing, helping to reduce
exhaust noise. The revised silencer
internals ensure that strict 2m-max
noise regulations are met (115 dB).
*
On North American models, revised internal construction results in a quieter silencer
that clears stricter 94 dB noise regulations.
*
Additional performance-oriented engine characteristics
The engine was tuned such that the torque curve follows the limit of running
resistance for as long as possible. (Unchecked, engine torque can exceed this limit,
resulting in wheel spin, which does nothing to help forward momentum.)
*
Efforts were made to achieve the widest possible torque band, so that traction
efficiency would be maximised for a greater part of the rev range.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 10
Lightweight titanium valves (IN: 31 mm; EX: 25 mm) reduce reciprocating weight
and offer high-rpm reliability. The ultra-light valves have extremely thin valve stems
on par with those found in supersport machines. The intake valves feature thicker
heads for increased strength and both intake and exhaust valves are formed from a
highly rigid, titanium material.
*
Crank web design increases offsetting moment for a high crankshaft balance factor.
At close to 60%, the balance factor of the ’11 KX250F is on par with our factory
racers. The high balance factor contributes to reduced engine vibration, smoother
power delivery and increased
performance in the mid-high rpm range.
*
32 mm thick, 117.8 mm wide radiators with wide fin and tube pitch offer resistance
to mud build-up while maintain cooling performance. The radiators are strong
enough that the reinforcing brackets could be eliminated, resulting in lower overall
weight.
*
Sprocket-style chain drive roller helps smooth engine braking by reducing the effect
of driveline lash when the rider gets off the gas quickly and play in the lower side of
the chain suddenly tightens. The additional control facilitates corner entry.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 11
HIGH-SPEED CHASSIS WITH FACTORY-STYLE
COMPONENTS & TUNING
The KX250F’s slim aluminium perimeter frame is a lightweight construction composed of
forged, extruded and cast parts. Chassis balance and settings were all set to suit
race-experienced riders. The centre of gravity and key dimensions (swingarm pivot,
output sprocket and rear
axle locations) were chosen so that the rear tyre would drive the bike forward (instead of
causing it to squat). For 2011, the high-speed chassis benefits from a new Separate
Function front Fork (SFF) with greatly reduced friction that offers increased riding comfort
and improved suspension performance. In addition to enhanced handling offered by the
SFF’s improved left/right balance, increased chassis flex and revised frame rigidity
balance offer lighter handling and increased turning performance. The highly acclaimed
high-speed stability of its predecessor remains unchanged.
Lighter-handling chassis
While the frame remains essentially the
same as that of the 2010 model, revised
rigidity balance results in a frame with
designed in moderate lateral flex.
Frame’s front and side hangers (engine mounting brackets), previously aluminium,
are now formed from steel, and are thinner (front: t6.0 mm >> t4.5 mm; side: t8.0
mm >> t4.5 mm).
*
The resultant increased lateral chassis flex enables lighter turning.*
The revised rigidity balance offers a number of benefits:
- increased rear wheel traction
- more planted feel from the front wheel
- enhanced cornering accuracy makes it easier for riders to follow the line they want
*
Reduced fork offset (23.5 mm >> 22.5 mm) also contributes to the lighter handling,
enhanced cornering accuracy and more planted feel of the front wheel. Additionally,
it also gives the bike a more compact feel.
*
Superior rear-wheel traction
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 12
The New Uni-Trak rear suspension
system mounts the suspension arm
below the swingarm, allowing a longer
rear suspension stroke. The longer
stroke in turn allows more precise
rear suspension tuning.
*
Extensive rider testing was conducted to determine the ideal linkage ratios and rear
shock absorber damping settings to achieve maximum rear wheel traction.
*
Race-oriented suspension: Separate Function Front Fork
Showa’s Separate Function Front Fork
(SFF) makes its first appearance on a
mass-production
motocrosser. The SFF separates damping
and shock absorption duties:
> Left fork tube: damping assembly
> Right fork tube: spring
The configuration offers both smooth action
and firm damping performance – a
combination
difficult to achieve with a conventional fork.
With only one spring, the friction generated between the spring(s) and fork inner
tube(s) is greatly reduced (approximately 25% less), resulting in extremely smooth
action throughout the fork stroke. (Illustrations A, B)
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 13
Being able to use a larger damper
piston not only enables smoother
action and makes firm damping
performance possible. (Illustration C)
*
Removing the damper assembly from
NEW the right fork tube frees up
space for a preload adjuster. Having a
preload adjuster greater simplifies the
task of setting fork preload or front
height. (With a conventional fork, only
the rear could be adjusted easily;
adjusting the front required fork tubes
to be disassembled and the use of
collars and special tools. With SFF,
both the front and rear preload/height
can be set quickly and easily.)
*
In addition to preload adjustment, the
racer-friendly SFF also facilitates
other maintenance chores like
adjusting damping and changing
springs.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 14
SFF offers improved left/right balance, which greatly enhances handling. Locating
the heavy spring in the right tube (and fine-tuning the left and right tube strength)
better offsets the previously unbalanced weight of the brake caliper and disc on the
left side.
*
A restrictor added on the damper
assembly side and a joint rod comp
added on the spring side ensure that
natural character is maintained.
Placement of the restrictor can be
used to change damping
characteristics; it contributes to
idealised damping character. The joint
rod comp ensures even left/right
damping force and contributes to
ideal fork rigidity.
*
A super-hard titanium coating on the
outer surface of the inner fork tubes
reduces sliding friction (and stiction)
and improves action, contributing to
the smoother ride. The increased
surface hardness of the dark navy
blue coating also helps to prevent
scratches and damage to the tubes.
(The KX250F is the only motocrosser
in its class to feature this race-ready
coating as a standard feature.)
*
Friction-reducing Kashima Coat on the inside of the fork outer tubes contributes to
smoother suspension action (especially at the initial part of the stroke) and a better
ride feel.
*
Race-oriented rear suspension
Rear shock damping settings, revised
to match the new SFF, offer
improved action and increased
absorption performance.
*
The rear shock features dual compression adjustability, allowing high-speed and
low-speed damping to be tuned separately.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 15
The rear shock also features the Kashima Coat on the tank cylinder.
The reduced friction smoothes suspension action.
*
Factory-style and other race-oriented components
Among the KX250F’s numerous factory-style components are its front and rear
petal disc brakes. In addition to helping reduce unsprung weight, the wave shapes
of the petal discs help clean the brake pads for more efficient braking performance.
*
Rear caliper guard protects the caliper from damage.*
Factory-style Renthal (standard-type)
aluminium handlebars are standard
equipment.
*
Rib-less rear hub and butted spokes reduced unsprung weight.*
Rims are coated in black alumite1 – just like our factory racers.*
Fork and rear shock adjusters have a blue alumite1 finish like our US factory racers.*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 16
Factory-style graphics complement the KX250F’s highly tuned performance.*
Rider interface
Designed with rider ergonomics in mind, the bodywork components offer the rider a slim
interface, the natural position makes it even easier for racers to go fast.
Formed using a double-injection
moulding process, 2-tone shrouds
contribute to the slim package.
*
2-tone side covers are also formed
using a double-injection moulding
process.
Like the shrouds, they contribute to
the slim package. A hole in the
right-side cover helps cool the
silencer.
*
The frame widens at the ankles to offer the rider better grip and narrows near the
bend below the seat to allow a slim riding position.
*
The seat uses a slip-resistant top surface for good grip when seated and smooth
sides for excellent rider mobility.
*
KEY FEATURES
2011MY KX250F MODEL INFORMATION PAGE 17
Revised pattern for the seat sides
offers more grip than before.
*
Seat urethane designed to keep the original shape longer.*
Wide (front-to-rear) footpegs designed to offer grip and superb feel at the pegs.*
The clutch cable boot features a large quick adjuster, making it easier for riders to
adjust play in the clutch cable.
*
The throttle grip has a unitised collar. The one-piece unit provides additional stability
during throttle operation.
*
Lightweight short-length grips feature a pattern designed to provide excellent grip.*
ADDITIONAL FEATURES
2011MY KX250F MODEL INFORMATION PAGE 18
Engine
Electrofusion treatment on cylinder
bore results in a surface with good 22
oil retention. Further, the molybdenum
on the surface of the cylinder bore
helps resist scorching, contributing to
durability.
*
Chassis
The alloy swingarm uses a cast front section, tapered hydroformed spars and
forged chain adjusters.
*
Swinging arm is longer to accommodate the larger rear sprocket, and is now
common with the KX450F. The chain is also longer: 112 links >> 114 links.
*
Large synthetic skid plate offers great protection with minimum weight.*
Front chain guide (chain slider) uses a thicker plastic lining, offering longer wear life.*
Other
Optional engine parts include magneto rotors with different inertias (8.5, 9.5 kg.cm2;
STD: 9.0 kg.cm2) and a 12T output sprocket (STD: 13T).
*
Optional chassis parts include handlebar holder for a ø28.6 mm bar (STD: ø22.2
mm), aluminium and steel rear sprockets (48-52T; STD: 50T), solid petal brake
rotors for wet races, and different springs for the front fork (8.7, 9.1, 9.5 N/mm; STD:
9.1 N/mm) and rear shock (47, 48.1, 49, 50, 51, 52, 53, 53.9 N/mm, STD: 51
N/mm).
*
An Fi indicator lamp (available as an
option) warns of any problem with the
Fi system.
*
COLOURS
2011MY KX250F MODEL INFORMATION PAGE 19
Lime Green with factory-style graphics
SPECIFICATIONS
2011MY KX250F MODEL INFORMATION PAGE 20
ENGINE
Engine type Liquid-cooled, 4-stroke Single
Displacement 249 cm³
Bore x stroke 77.0 x 53.6 mm
Compression ratio 13.2:1
Valve/Induction system DOHC, 4 valves
Fuel system Carburettor: Keihin FCR-MX37
Ignition Digital AC-CDI
Starting Primary kick
Lubrication Forced lubrication, semi-dry sump
DRIVETRAIN
Transmission 5-speed, return
Final Drive Chain
Primary reduction ratio 3.350 (67/20)
Gear ratios: 1st 2.142 (30/14)
Gear ratios: 2nd 1.769 (23/13)
Gear ratios: 3rd 1.444 (26/18)
Gear ratios: 4th 1.200 (24/20)
Gear ratios: 5th 1.045 (23/22)
Final reduction ratio 3.692 (48/13)
Clutch Wet multi-disc, manual
FRAME
Frame type Perimeter, aluminium
Wheel travel, front 315 mm
Wheel travel, rear 310 mm
Tyre, front 80/100-21 51M
Tyre, rear 100/90-19 57M
Rake/Trail 27.7°/122.3 mm
Steering angle, left / right 42° / 42°
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Kawasaki KX250F - 2011 Information Manual

Kawasaki
Brand
Kawasaki
Model
KX250F - 2011
Category
Motorcycles
Type
Information Manual
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