23 maj 2018 ID: 131231
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2019 HONDA CRF250RX

2019 HONDA CRF250RX

Model updates: The new CRF250RX arrives in cross-country specification to further strengthen Honda’s off-road line-up. Sharing the frame and engine hardware of the CRF250R moto-crosser, it is fully adapted to its role, with 8.5L fuel tank, forged aluminium sidestand and 18-inch rear wheel, plus revisions to power delivery and suspension settings. It also features 3-level HRC Launch Control as standard.

 

Contents:

1 Introduction

2 Model overview

3 Key features

4 Technical specifications

 

1. Introduction

Honda’s CRF250R has shown itself a worthy weapon for battle in the hard-fought MX2 class. For 18YM, it made a giant leap, with a full model change that shared the ‘Absolute Holeshot’ philosophy of the 17YM CRF450R, featuring a new seventh-generation frame, revised geometry and Showa suspension – plus a brand new DOHC engine.

Now Honda is expanding the CRF250R platform and adding a cross-country option to the range; the CRF250RX mirrors the CRF450RX and takes the 19YM CRF250R as a base. Fast, agile and easy to ride, it’s a potent machine, with modifications that tailor it perfectly for its new role, making it equally at home speeding up a root-strewn climb or slicing precious seconds off a special Enduro test.

2. Model Overview

In common with the CRF450RX, the CRF250RX uses the rock-solid base of its moto-cross sibling and adds the essential ingredients for closed-course cross-country riding. Thus, it features a 8.5L fuel tank (like the CRF450RX), and also uses an 18-inch rear wheel plus revised suspension settings front and rear. Fuelling and ignition mapping have also been adjusted to deliver a softer power delivery compared to the moto-crosser, and a forged aluminium sidestand is fitted as standard.

The CRF250RX also benefits from the upgrades made to the CRF250R for 19YM: engine changes which boost low-rpm torque to gain time out of slower corners

(thanks to revisions from the throttle body all the way to the exhaust), a new front brake caliper, Renthal Fatbars and 3-mode HRC Launch Control to help any rider gain a good start, every time.

 

3. Key Features

 

3.1 Engine

  • Strong bottom-end torque, same top-end power as CRF250R
  • Benefits from 19YM CRF250R upgrades: revised throttle body, cylinder head, intake and exhaust for improved low-down performance
  • 3 level HRC Launch Control optimises start performance

Strong peak power is a CRF250R core strength, and was further boosted by a massive 9% for the all-new 18YM machine. For 19YM, the base engine has been further refined with the focus on low-rpm improvements. Sharper jump out of slow-speed corners has been achieved with a 2mm smaller (now 44mm) diameter throttle body, to speed up low-rpm air flow. The inlet and exhaust ports have been re-shaped and the exhaust valve cam ‘closing’ profile also reduced by 2°, all to boost torque.

The CRF250RX shares the 19YM engine with is moto-cross sibling for a fully-rounded performance throughout the range – with the same peak power – but has revised fuelling and ignition mapping to soften the power delivery.

The fundamentals of the engine are: bore and stroke of 79 x 50.9mm, with a 4.5mm cylinder offset to reduce friction and compression ratio of 13.9:1. Titanium valves - 33mm inlet and 26mm exhaust. Lift is 10.5mm inlet and 9.5mm exhaust and the valve angle is set at 20.5°. The valve springs themselves are oval in section; the inlet valves are fed by symmetrical straight-shot downdraft intakes, which are shorter for improved high rpm snap.

The piston is a Bridged Box design. Its rigidity converts combustion pressure into high output efficiency; for YM19 a 5-hole piston oil jet replaces the previous 4-hole design, improving piston cooling and optimising ignition timing.

A scavenge oil pump system reduces friction and ‘pumping’ losses at high rpm, by discharging oil and air in the crankcase and maintaining negative pressure. The oil also lubricates the clutch and gearbox, with a total oil capacity of 1250cm3. The combined oil pump/drive gear, oil filter and oil way are on the right side of the engine – the oil’s path around the engine is short and straightforward.

Valve train lubrication is routed through the cylinder head to the inside of both inlet and exhaust cam, directly feeding the sliding surface of cam and rocker arm. The 5-speed gearbox drives a sealed 520 chain through a 13T front and 48T rear sprocket.

The rider controls and displays – engine stop button, EFI warning, EMSB mode button and LED indicator – are rationalised together and sited on the left handlebar:

New for YM19 (and as with the CRF250R) HRC’s Launch Control system gives any rider the best option for a strong start and has 3 modes to choose from:

Level 3 – 8,250rpm, muddy conditions/beginner

Level 2 – 8,500rpm, dry conditions/basic

Level 1 – 9,500rpm, dry conditions/expert

Activating HRC Launch Control is easy – to turn on, pull in the clutch and push the Start button (on the right). The LED will blink once for Level 1 selection. Push the Start button again, for 0.5s or longer, and the LED will blink twice for Level 2. Repeat the process and the LED will blink 3 times, indication Level 3 has been chosen.

The Engine Mode Select Button (EMSB) alters the engine’s characteristics and three maps are available to suit riding conditions or rider preference: Mode 1 (Standard), Mode 2 (Smooth) and Mode 3 (Aggressive). The LED also displays Mode selected.

 

3.2 Chassis

  • Renthal Fatbar has 4-way adjustable positioning
  • DID rims finished in black, 18-inch rear wheel
  • Shares CRF250R upgrades for 19YM: new front brake caliper and hose for improved stopping performance; redesigned sump guard and fork protectors

The CRF250RX uses the same tapered-spar aluminium frame as the CRF250R, which returns excellent feedback and rear wheel grip due to its low centre of gravity.

Unchanged in its transition to RX-spec. it does use a new twin-piston front brake caliper – common with the YM19 CRF450R – which has 30 and 27mm diameter pistons. This allows for a lighter body and, along with low expansion rate brake hose, improved brake feel and staying power. It works on a 260mm wave-pattern disc, matched by a rear 240mm wave-pattern disc and single-piston caliper.

The Renthal Fatbar reduces the weight of the steering system and flexes for optimal comfort; the top yoke features two handlebar-holder locations for moving the handlebar rearward and forward by 26mm. When the holder is turned 180 degrees, the handlebar can be moved an additional 10mm from the base position, resulting in four total unique riding positions.

Rake and trail are set at 27.3°/115mm, with wheelbase of 1486mm. Wet weight is 111kg. The fully adjustable 49mm Showa USD coil spring fork is a version of the Showa ‘factory’ fork supplied to MX race teams in the Japanese championship; the cylinder has a 25mm diameter, the rod 14mm and the compression piston 39mm. The Showa rear shock is also fully adjustable

Lightweight DID aluminium rims, with directly attached spoke pattern layout are now finished in black; the front is a 21 x 1.6in, the rear an 18 x 2.15in. Fitted as standard equipment are Dunlop’s Geomax AT81 Enduro tyres, 90/90-21 front and 110/100-18 rear.

Like its big brother the CRF250RX uses an 8.5L plastic fuel tank, giving a potential range of 65km. The radiator shroud is CRF250RX-specific, while the smooth external lines of the plastics help the rider move easily and the narrow frontal area and front mudguard directs an efficient funnel of air to the radiator. A forged aluminium sidestand tucks neatly out of the way when not in use.

The bodywork uses durable film inset graphics that cover a wide area with scratch-resistant style; the engine sump guard has been redesigned to improve engine cooling and fork protector modified to reduce chance of stone damage.

 

4. Technical Specifications

 

ENGINE

 

Type

Liquid-cooled 4-stroke single DOHC

Displacement

249.4cc

Bore ´ Stroke

79mm x 50.9mm

Compression Ratio

13.9 : 1

Oil Capacity

1.3 litres

FUEL SYSTEM

 

Carburation

Fuel injection

Fuel Tank Capacity

8.5 litres

ELECTRICAL SYSTEM

 

Ignition

Full transistor

Starter

Electric

DRIVETRAIN

 

Clutch Type

Wet multiplate

Transmission Type

Constant mesh

Final Drive

Chain

FRAME

 

Type

Aluminium twin tube

CHASSIS

 

Dimensions (L´W´H)

2185mm x 827mm x 1262mm

Wheelbase

1,486mm

Caster Angle

27.3 degrees

Trail

115mm

Seat Height

961mm

Ground Clearance

329mm

Kerb Weight

111kg

SUSPENSION

 

Type Front

49mm Showa coil-sprung fork

Type Rear

Showa monoshock using Honda Pro-Link system

WHEELS

 

Type Front

Aluminium spoke

Type Rear

Aluminium spoke

Tyres Front

90/90-21 Dunlop AT81

Tyres Rear

110/100-18 Dunlop AT81

BRAKES

 

Front

260mm hydraulic wave disc

Rear

240mm hydraulic wave disc

 

All specifications are provisional and subject to change without notice.

 

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