Yamaha YTZ250S 1986 Service Manual page 136

B. Chassis
Item
~I
YTZ250S
Steering System:
Steering Bearing Type
Ball and Taper Roller Bearing
No./Size of Steel Balls Upper 19 pcs/1/4 in
Front Suspension:
Front Fork Travel 255 mm (10 .0 in)
Fork Spring Free Length Long 547 .1 mm (22.6 in)
Short 42.3 mm (1 .67 in)
<Limit>
Long < 569.1 mm (22.4 in) >
Short <37.3 mm (1.47 in»
Spring Rate/Stroke
Kl
=
4.31 N/ mm (0 .44 kg / mm, 24.6 Ib /in)
0-100 mm (0-3.93 in)
K2
=
5.39 N/ mm (0.55 kg /mm, 30.8 Ib /in)
100 - 255 mm (3 .93 -10 .0 in)
Optional Spring Yes
Spring Rate/Stroke Soft
Kl
=
3.92 N/ mm (0.40 kg / mm, 22.4 Ib / in)
0-100 mm (0-3.93 in)
K2
=
4.90 N/ mm (0.50 kg / mm, 28.0 Ib /in )
100-255 mm (3.93-10.0 in)
Hard Kl
=
4.90 N/ mm (0.50 kg / mm, 28.0 Ib/in)
0-100 mm (0-3.93 in)
K2
=
5.88 N/ mm (0.60 kg / mm, 33.6 Ib/in)
100-255 mm (3 .93-10.0 in)
Oil Capacity of
418 cm 3 (14.7 Imp oz, 13.9 US oz)
Oil Level 180 mm (7.09 in)
(From top of inner tube fully compressed without
spring .)
Oil Grade
Yamaha fork oil 10wt or equivalent
Enclosed Air Pressure
Std.
o
kPa (0 kg/ cm
2 ,
0 psi)
max. 58.8 kPa (0.6 kg / cm
2 ,
8.53 psi)
Rear Suspension :
Shock Absorber Travel
92 mm (3.62 in)
Spring Free length 240.5 mm (9.47 in)
Fitting Length 235.5 mm (9 .25 in)
Spring Rate, STD
K
=
73.5 N/ mm (7 .5 kg / mm, 420 Ib /in) / 0-92 mm
(0-3.6 in)/No paint
Optional Spring Yes
Spring Rate, Soft
K
=
68.6 N/ mm (7.0 kg / mm, 392 Ib /i n) / 0-92 mm
(0-3.6 in)/Blue
Hard
K
=
78.4 N/mm (8.0 kg / mm, 448 Ib /in) / 0-92 mm
(0-3.6 in)/Black
Enclosed Gas Pressure
1.177 kPa (12 kg / cm
2 ,
113.7 psi)
Max.-Min .
<784-1,480 kPa (8-15 kg / cm
2 ,
114-213 psi»
Rear Arm:
Swingarm Free Play Limit
End < 1.0 mm (0.04 in) >
Side <0.3 mm (0.012 in) >
6-12