Yamaha YZ250FX 2020 User Manual

CRANKSHAFT AND BALANCER SHAFT
5-71
EAM30491
REMOVING THE CRANKSHAFT
1. Remove:
• Balancer shaft “1”
TIP
Remove the balancer shaft with its flat side “a”
facing the crankshaft.
2. Remove:
• Crankshaft assembly “1”
TIP
Remove the crankshaft assembly by using the
crankcase separating tool “2”.
EAM30492
CHECKING THE CRANKSHAFT
1. Measure:
• Crankshaft runout
Out of specification  Replace the crank-
shaft, bearing or both.
TIP
Turn the crankshaft slowly.
2. Measure:
• Crank assembly width “a”
Out of specification  Replace the crank-
shaft.
3. Check:
• Crankshaft sprocket “1”
Damage  Replace the crankshaft.
4. Check:
• Crankshaft journal oil passage
Obstruction  Blow out with compressed air.
Crankcase separating tool
90890-04152
Crankcase separating tool
YU-A9642
1
a
a
2
1
Runout limit
0.030 mm (0.0012 in)
Crank assembly width
55.93–56.00 mm (2.202–2.205 in)
1

Yamaha YZ250FX 2020 Specifications

General

Engine Type	Liquid-cooled, 4-stroke, DOHC, 4-valve
Displacement	250cc
Bore x Stroke	77.0mm x 53.6mm
Compression Ratio	13.5:1
Fuel System	Fuel Injection
Ignition	TCI
Final Drive	Chain
Front Brakes	Hydraulic disc, 270mm
Rear Brakes	Hydraulic disc, 245mm
Length	85.6 in
Width	32.5 in
Height	50.4 in
Seat Height	37.6 in
Ground Clearance	12.8 in
Front Suspension	KYB® Speed-Sensitive System inverted fork; fully adjustable, 12.2-in travel
Front Tire	80/100-21
Rear Tire	110/100-18