Honda Crf250l Service Manual

							MEMO
dummyhead
dummyhead 
						

							14-1
14
dummytext
14. CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
SERVICE INFORMATION ···························14-2
TROUBLESHOOTING·································14-2
COMPONENT LOCATION ··························14-3
CRANKCASE SEPARATION··················\
····14-4
CRANKSHAFT ··················\
··················\
········14-6 MAIN JOURNAL BEARING ··················\
······ 14-7
TRANSMISSION ······································· 14-10
BALANCER··············································· 14-14
CRANKCASE BEARING 
REPLACEMENT ······································· 14-15
CRANKCASE ASSEMBLY ··················\
····· 14-18 
						

							14-2
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCERSERVICE INFORMATION
GENERAL
 • This section covers crankcase separation for service of the crankshaft, transmission and balancer.
 • The crankcase must be separated to service the crankshaft, ba lancer and transmission. To service these parts, the engine must
be removed from the frame.
 • The following components must be removed before separating the crankcase.
– Camshaft (page 10-6)
– Cylinder head (page 10-13)
– Cylinder/piston (page 11-3)
– Clutch (page 12-9)
– Gearshift linkage (page 12-14)
– Oil pump (page 8-4)
– Primary drive gear (page 12-17)
– Flywheel (page 13-5)
– Neutral switch (page 20-13)
– Starter motor (page 6-4)
– Engine (page 15-4)
 • Be careful not to damage the crankcase mating surfaces when servicing.
 • Clean the oil passages before assembling the crankcase halves.
 • Prior to assembling the crankcase halves, apply sealant to  their mating surfaces. Wipe off excess sealant thoroughly.
 • The main journal bearing inserts are select fit and are ident ified by color codes. Select replacement bearing from the code
tables. After selecting a new bearing, recheck the oil clearance. Incorrect oil clearance can cause major engine damage.
TROUBLESHOOTING
Excessive engine noise
 • Worn, seized or chipped transmission gear
 • Worn or damaged transmission bearing
 • Worn or damaged connecting rod big end bearing
 • Worn main journal bearing
 • Worn connecting rod small end
 • Worn balancer shaft bearing
 • Improper balancer timing
Hard to shift
 • Bent shift fork
 • Bent shift fork shaft
 • Damaged shift drum guide groove
 • Damaged shift fork guide pin
 • Bent shift fork claw
 • Damaged gearshift spindle
 • Loose shift drum stopper arm bolt
Transmission jumps out of gear
 • Worn gear dogs or dog holes
 • Damaged shift drum guide groove
 • Worn shift fork guide pin
 • Worn shift fork groove in gear
 • Worn shift fork shaft
 • Bent shift fork shaft
 • Weak or broken gearshift spindle return spring
Engine vibration
 • Excessive cr ankshaft runout
 • Improper balancer timing 
						

							14-3
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
COMPONENT LOCATION
10 N·m (1.0 kgf·m, 7 lbf·ft)
44 N·m (4.5 kgf·m, 32 lbf·ft) 
						

							14-4
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
CRANKCASE SEPARATION
Refer to Service Information (page 14-2) for removal of
necessary parts before di sassembling the crankcase.
Remove the tensioner pivot bolt [1], collar [2] and cam
chain tensioner [3].
Remove the cam chain [4] and timing sprocket [5].
Check the cam chain tensio ner [1] for excessive wear
or damage, replace it if necessary.
Install a 3 mm (0.12 in) O.D. pin [1] into the hole [2] of
the balancer driven gear assembly [3].
Insert the gear holder [1] between the balancer drive
gear [2] and balancer driven gear assembly [3].
Loosen the balancer shaft nut [4].
Remove the nut, washer [5], balancer driven gear
assembly and balancer drive gear.
For balancer driven gear disassembly (page 14-14).
[3][1]/[2]
[4][5]
[1]
[3][1][2]
TOOL:
Gear holder, M2.5 07724-0010100
[2]
[3]
[1][4]/[5] 
						

							14-5
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
Remove the woodruff key [1] from the balancer shaft.
Loosen the crankcase bolts [1] in a crisscross pattern in
2 or 3 steps, and remove the bolts.
Place the crankcase assembly with the right crankcase
down.
Carefully separate the left  crankcase [1] from the right
crankcase [2] while tapping them at several locations
with a plastic hammer.
Remove the dowel pins [1] and O-ring [2].[1]
[1]
Do not pry the
crankcase halves
with a screwdriver.
[2]
[1]
[1]
[1]/[2] 
						

							14-6
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
CRANKSHAFT
REMOVAL
Separate the crankcase halves (page 14-4).
Remove the crankshaft [1] from the right crankcase.
INSPECTION
Inspect the following parts for scratch, damage,
abnormal wear and deformation. Replace if necessary.
– Crankshaft
– Connecting rod
– Timing sprocket
Measure each part according to CRANKCASE/
CRANKSHAFT/TRANSMISSION BALANCER
SPECIFICATIONS (page 1-7).
Replace any part if it is out of service limit.
CRANKSHAFT RUNOUT
Place the crankshaft on V-blocks.
Set the dial indicator on the crankshaft.
Rotate the crankshaft two revolutions (720°) and read
the runout.
INSTALLATION
Apply molybdenum oil solution to the connecting rod big
end sliding surface.
Apply molybdenum oil solution to the crankshaft main
journal bearing sliding surface.
Install the crankshaft [1]  into the right crankcase.
Assemble the crankcase (page 14-18).
[1]
SERVICE LIMIT: 0.03 mm (0.001 in)
29.0 mm 
(1.14 in)6.0 mm 
(0.24 in)
[1] 
						

							14-7
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
MAIN JOURNAL BEARING
BEARING INSPECTION
Remove the following:
– Crankshaft (page 14-6)
– Transmission (page 14-10)
– Balancer shaft (page 14-14)
Clean off any oil from the bearings.
Check the main journal bearings [1] for unusual wear,
damage or peeling and replace them if necessary.
MAIN JOURNAL OIL CLEARANCE
Measure and record the main journal bearing I.D. at
between the bearing groove and crankcase outside end
of the bearing, and 90 degrees to the index mark [2].
Clean off any oil from the crankshaft journals.
Measure and record the crankshaft main journal O.D.
Calculate the oil clearance between the crankshaft
main journal and main journal bearing.
If the clearance exceeds the service limit, select the
main journal bearing (page 14-7).
BEARING SELECTION
Remove the following:
– Crankshaft (page 14-6)
– Transmission (page 14-10)
– Balancer shaft (page 14-14)
Set a special tool and hydraulic press on the outside of
the crankcase.
Press the main journal bearings [1] toward the inside of
the crankcase.
90°
[1]
[2]
INSIDE
OUTSIDE
MEASUREMENT 
POINT
SERVICE LIMIT: 33.975 mm (1.3376 in)
SERVICE LIMIT: 0.075 mm (0.0030 in)
TOOLS:
[1] Driver, 30 x 36 mm 07HMF-KR10101
[2] Base, 42 mm 07GAF-SD40200
[1]
[2]
[1] 
						

							14-8
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
Measure and record the crankcase main journal
bearing support I.D. at 90 degrees to the index mark [1].
Depending upon the results of the above
measurements there are four possible scenarios for
main journal bearing selection:
 • Crankshaft and crankcase are replaced
 • Crankcase only is replaced
 • Crankshaft only is replaced
 • Main journal bearings only are replaced
Carefully refer to the following instructions and tables
for main journal bearing selection.
Record the bearing support I.D. code [1] letter.
Letters A, B or C on each crankcase is the code for the
crankcase main journal bearing support I.D.
Cross-reference the crankshaft and crankcase codes to
determine the replacement bearing color. SERVICE LIMIT: 38.036 mm (1.4975 in)
90°
[1]
[1]
BEARING SUPPORT 
I.D. CODE
(Crankcase replaced) BEARING SUPPORT I.D. MAIN JOURNAL O.D.
33.985 – 34.000 mm (1.3380 – 1.3386 in)
(Crankshaft replaced) 33.975 – 33.985 mm
(1.3376 – 1.3380 in)
A 38.000 – 38.006 mm
(1.4961 – 1.4963 in) C (Brown)
1.996 – 1.999 mm
(0.0786 – 0.0787 in) B (Black)
1.999 – 2.002 mm
(0.0787 – 0.0788 in)
B 38.006 – 38.012 mm
(1.4963 – 1.4965 in) B (Black)
1.999 – 2.002 mm
(0.0787 – 0.0788 in) A (Blue)
2.002 – 2.005 mm
(0.0788 – 0.0789 in)
C 38.012 – 38.018 mm
(1.4965 – 1.4968 in) A (Blue)
2.002 – 2.005 mm
(0.0788 – 0.0789 in) O.S. G (Pink)
2.005 – 2.008 mm
(0.0789 – 0.0791 in)
– 38.018 – 38.024 mm
(1.4968 – 1.4970 in) O.S. G (Pink)
2.005 – 2.008 mm
(0.0789 – 0.0791 in) O.S. F (Yellow)
2.008 – 2.011 mm
(0.0791 – 0.0792 in)
– 38.024 – 38.030 mm
(1.4970 – 1.4972 in) O.S. F (Yellow)
2.008 – 2.011 mm
(0.0791 – 0.0792 in) O.S. E (Green)
2.011 – 2.014 mm
(0.0792 – 0.0793 in)
– 38.030 – 38.036 mm
(1.4972 – 1.4975 in) O.S. E (Green)
2.011 – 2.014 mm
(0.0792 – 0.0793 in) O.S. D (Red)
2.014 – 2.020 mm
(0.0792 – 0.0795 in) 
						

							14-9
dummyhead
dummyhead
CRANKCASE/CRANKSHAFT/TRANSMISSION/BALANCER
BEARING INSTALLATION
Apply engine oil to new bearing [1] surface.
Set new bearings to the metal installer as shown.
Tighten the bolts [2] alternately in several steps.
Set the bearings [1] and special tools assembly on
inside of the crankcase, fitting the bearing edge in the
crankcase main journal.
Align the mating line of the bearings with the index mark
[2] on the crankcase as shown.
Set the crankcase and special tools on the hydraulic
press.
Make sure the metal installer mating line is aligned with
the index mark on the crankcase. BEARING THICKNESS: O.S. D (Red): Thick
O.S. E (Green):
O.S. F (Yellow):
O.S. G (Pink): Middle
A (Blue):
B (Black):
C (Brown): Thin
IDENTIFICATION COLOR
TOOL:
Metal installer set 070MF-KYJ0100
4.0 mm 
(0.16 in)
[2][1]
[1]
[2]
TOOLS:
[1] Metal installer set 070MF-KYJ0100
[2] Base, 42 mm 07GAF-SD40200
[1]
[2]