Husqvarna WR 250/2005, Workshop Manual

Page: 20 / 368

N° 8000A4433 (06-04)
A.6
GENERAL
ENGINE
Single-cylinder, two-stroke engine, with lamellar suction and
mechanical control H.T.S. valve on the exhaust system.
Bore ........................................................66,4 mm/2.61 in.
Stroke.........................................................72 mm/2,83 in.
Capacity .............................................249,3 cm
3 /15.21 cu.in.
Compression ratio (with closed ports) ..............................8,4:1
FUEL FEEDING
Intake setting by lamellar valve.
PORT TIMING
TRANSFER: ................................................................116°
EXHAUST: .................................................................184°
Carburetor: ...........................................................Mikuni TMX 38
LUBRICATION
ENGINE
3% of oil-gasoline mix (during running) NOT LESS than 2%
when running is over.
SHIFTING and MAIN TRANSMISSION: Through the oil contai-
ned in the engine block.
COOLING
With liquid circulation through a pump. Two radiators are pro-
vided in the thermal assembly front.
IGNITION
Capacity discharge electronic start with variable advance.
Manufacturer .....................................................KOKUSAN
Ignition advance
(piston stroke before T.D.C.) ...............0,5 mm/0.0197 in. (8°)
Spark plug make and type: ..................“NGK” BR8 EG (250);
Electrode gap.......................0,6÷0,7 mm/0.0236÷0.0275 in.
STARTING
Kick-start.
TRANSMISSION
Cluster constant-mesh gears.
Primary ratio ...........................................Z 27/69= 1:2,555
Gear ratios
1
st
Z 14/30=1:2,142
2
nd
Z 16/28=1:1,750
3 rd Z 16/23=1:1,437
4 th Z 19/23=1:1,210
5
th
Z 19/20=1:1,053
Final drive ratio ........................................Z13/48= 1:3,692
Gearing chain ............................(WR) REGINA 135 ORN-A
or D.I.D. 520-V6(OR), 5/8”x1/4”
Total ratios
1 st ..............20,220
2
nd
.............16,513
3
rd
............13,564
4
th
..............11,422
5 th ..............9,932
Oil-bath multi-disc clutch type.
BRAKES
Front brake
Perforated fixed disc with hydraulic control and floating caliper.
Disc diameter ..........................................260 mm/10.23 in.
Brake caliper .........................................................BREMBO
Pad area............................................33,4 cm
2
/5.18 sq.in.
Rear brake
Perforated floating disc with hydraulic control and floating caliper.
Disc diameter ..........................................220 mm/8.661 in.
Brake caliper .........................................................BREMBO
Pad area............................................29,5 cm
2 /4.57 sq.in.
FRAME
Double cradle; rear frame. Made up of rectangular and square
high tensile steel tubes.
Steering angle .......................................................45° each
Steering axis angle.........................................................26°
Front fork caster ........................................114 mm/4.49 in.)
SUSPENSIONS
Front suspension
Telescopic-hydraulic up-side down fork with led pin, adjustable
in compression and rebound.
Manufacturer...................................................MARZOCCHI
Legs diameter ..............................................45 mm/1.77 in.
Front wheel stroke(on the sliding axis) ...........300 mm/11.8 in.
Rear suspension
Light alloy swinging fork with progressive leverage suspensions
(SOFT DAMP system) and hydraulic single-damper with helical
spring. The hydraulic brake compression (double), extension,
and the spring preload can be adjusted.
Damper make .........................................................SACHS
Rear wheel vertical travel ............................320 mm/12.6 in.
WHEELS
Light alloy front rim.
Manufacturer and type ...............................TAKASAGO Excel
Dimensions .........................................................1,60"x21"
Light alloy
rear rim.
Manufacturer and type ...............................TAKASAGO Excel
Dimensions ....................................................... 2,15”x18”
TYRES
Front
Make ................................................. “Michelin” or “Pirelli”
Type................................. Enduro Competition 3 or MT 71A
Dimensions ....................................................... 90/90-21”
Inflation pressure (cold):...........0,9÷1,0 Kg/cm
2
(12,8÷14,2 psi)
Rear
Make ................................................. “Michelin” or “Pirelli”
Type .....................................Enduro Competition 3 or MT 81
Dimensions ..................................................... 140/80-18”
Inflation pressure (cold):...........0,8÷0,9 Kg/cm
2
(11,4÷12,8 psi)
A-250 2005 25-06-2004 15:11 Pagina 6