Honda Crf 250 M Manual

							Servicing Your Honda47
Throttle
Throttle Inspection
(1) throttle
1. Check that the throttle assembly is positioned
properly and the securing bolts are tight.
2. Check for smooth rotation of the throttle (1)
from fully open to fully closed in all steering
positions.  If there is a problem, see your
Honda dealer.
3. Inspect the condition of the throttle cables
from the throttle grip down to the carburetor.
If the cable is kinked or chafed, have it
replaced.
4. Check the cables for tension or stress in all
steering positions.
5. Lubricate the cables with a commercially-
available cable lubricant to prevent premature
rust and corrosion.
(1) 
						

							Engine Idle Speed
48Servicing Your Honda
The best way to assure proper carburetion is to
see your Honda dealer for regularly scheduled
servicing, including carburetor adjustment.
Remember, idle speed adjustment is not a
“cure-all” for other problems in your engine’s
fuel-delivery system. Adjusting the idle will not
compensate for a fault elsewhere.
The engine must be at normal operating
temperature for accurate idle speed adjustment.
For information about high altitude carburetor
adjustment, see page 143.Idle Speed Adjustment
Refer to Safety Precautionson page 19.
1. Turn the pilot screw (1) in until it is lightly
seated and record the number of turns. Turn
the pilot screw out the same number of turns.2. If the engine is cold, start it and warm it up
three minutes. Then shut it off.
3. Connect a tachometer to the engine.
4. Shift into neutral. Start the engine.
5. Keep the motorcycle in an upright position.
6. Adjust idle speed with the throttle stop screw
(2).
Idle speed:
1,700 ± 100 rpm
(1)
(1) pilot screw(2)
(2) throttle stop screw 
						

							Servicing Your Honda49
Clutch System
Refer to Safety Precautionson page 19.
Clutch Lever Adjustment
The distance between the tip of the clutch lever
and the grip may be adjusted.
Make sure to adjust the clutch lever freeplay after
the clutch lever position adjustment or clutch
cable disconnected.
(1) lock nut (2) adjuster
1. Loosen the lock nut (1).
2. To position the clutch lever farther away from
the handgrip, turn the adjuster (2)
counterclockwise. To position the clutch lever
closer to the handgrip, turn the adjuster
clockwise.
3. Tighten the lock nut.
4. Adjust the clutch lever freeplay.
Clutch Freeplay
(1) clutch lever
Inspection
Check freeplay.
Freeplay:
3/8 – 3/4 in (10 – 20 mm)
If necessary, adjust to the specified range.
Improper freeplay adjustment can cause 
premature clutch wear.
Cable End 
Adjustment
Minor adjustments are generally made with the
clutch cable end adjuster.
Cable end adjuster:
(2) cable end adjuster
(+) increase free play
(–) decrease free play
1. Turn the cable end adjuster (2) to obtain the
specified freeplay.
2. Check the freeplay again.If the adjuster is threaded out near its limit and
the correct freeplay cannot be reached, turn the
adjuster in direction (+) until it seats lightly and
then turn it out one turn in direction (–). Make
the adjustment with the integral cable adjuster.
Integral Cable 
Adjustment
The integral cable adjuster is used if the cable
end adjuster is threaded out near its limit — or
the correct freeplay cannot be obtained.
(3) lock nut (+) increase
(4) cable adjuster (–) decrease
(5) cable end adjuster
1. Turn the cable end adjuster (5) in direction (+)
until it seats lightly and then turn it out 5 turns.
2. Loosen the lock nut (3).
3. Turn the integral cable adjuster (4) to obtain
the specified freeplay 3/8 – 3/4 in (10 – 20
mm).
4. Tighten the lock nut.  Check the freeplay.
5. Start the engine, pull the clutch lever in, and
shift into gear.  Make sure the engine does not
stall and the motorcycle does not creep.
Gradually release the clutch lever and open
the throttle. Your CRF should move smoothly
and accelerate gradually.
If you can’t get proper adjustment, or the clutch
does not work properly, the cable may be kinked
or worn, or the clutch discs may be worn.  See
your Honda dealer or refer to the official Honda
Service Manual (page 152).
(1)
(2)
(1)
(2)
(–)
(+)
(4)
(3)(5)
(–)
(+) 
						

							50Servicing Your Honda
Clutch System
Other Inspections & Lubrication
•Check that the clutch lever assembly is 
positioned properly and the securing bolts are
tight.
•Check the clutch cable for kinks or signs of
wear.  If necessary, have it replaced.
•Lubricate the clutch cable with a
commercially-available cable lubricant to
prevent premature wear and corrosion.
Clutch Operation
1. Check for smooth clutch lever operation.  If
necessary, lubricate the clutch lever pivot or
clutch cable.
2. Check the clutch cable for deterioration,
kinks, or damage.
Clutch Cover/Disc/Plate Removal
1. Drain the transmission oil (page 40).
2. Remove the rear brake pedal (1) by removing
its pivot bolt (2).
(1) rear brake pedal (2) pivot bolt
3. Remove the five clutch cover bolts (3) and
clutch cover (4).
(3) clutch cover bolts (4) clutch cover
4. Remove the five clutch spring bolts (5) and
clutch springs.
Loosen the bolts in a crisscross pattern in 2 or 3
progressive steps.5. Remove the clutch pressure plate (6).
(5) clutch spring bolts (6) clutch pressure plate
6. Remove the clutch lifter (7) and clutch lifter
rod (8).
7. Remove the eight clutch discs and seven
clutch plates (9).
Turn the lifter bearing plate of the clutch lifter
bearing with your finger.  The bearing plate
should turn smoothly and quietly.  Discard the
clutch lifter if the bearing plate does not turn
smoothly.
(7) clutch lifter (9) clutch discs and plates
(8) clutch lifter rod 
(2)(1)
(3)
(4)
(5)
(6)
(7)(9)
(8) 
						

							Servicing Your Honda51
Clutch System
Clutch Disc Inspection
Replace the clutch discs (1) if they show signs of
scoring or discoloration.
Measure the thickness of each clutch disc.
Service Limit:
0.112 in (2.85 mm)
Replace the clutch discs and clutch plates as an
assembly.
(1) clutch disc
Clutch Spring Inspection
(1) clutch spring
Measure the free length of each spring.
Service Limit:
1.46 in (37.2 mm)
If one or more springs are beyond the service
limit, replace the springs as a set.
Clutch Disc/Plate Installation
1. Coat the clutch plates (1) with transmission
oil.
2. Install the eight clutch discs (2) and seven
clutch plates alternately, starting with a clutch
disc.
(1) clutch plates (2) clutch discs
3. Apply grease to the clutch lifter rod (3).
4. Insert the clutch lifter rod into the mainshaft.
5. Install the clutch lifter (4) onto the rod.
(3) clutch lifter rod (4) clutch lifter
6. Install the clutch pressure plate (5).
7. Install the five clutch springs and bolts (6).
8. Tighten the bolts in a crisscross pattern in 2 or
3 steps, to the specified torque:
9 lbf·ft (12 N·m, 1.2 kgf·m)
(5) clutch pressure plate    (6) clutch spring bolts
9. Install a new O-ring (7) in the groove of the
clutch cover (8).
(7) O-ring (8) clutch cover
(1)
(1)
(2)(1)
(4)
(3)
(5)
(6)
(8)
(7)
(cont’d) 10. Install the cover by tightening the five cover
bolts to the specified torque:
7 lbf·ft (10 N·m, 1.0 kgf·m) 
						

							52Servicing Your Honda
Clutch System
11. Lubricate the O-ring (9), rear brake pedal (10)
pivot and pivot bolt (11) with Honda Lithium
Grease and tighten the pivot bolt to the
specified torque:
27 lbf·ft (37 N·m, 3.8 kgf·m)
Connect the brake pedal return spring (12) if
it was removed.
(9) O-ring (11) pivot bolt
(10) rear brake pedal (12) return spring
12. Fill the crankcase with transmission oil (page
40).
(12)
(10)
(11)(9) 
						

							Servicing Your Honda53
Hot Start Lever
Refer to Safety Precautions on page 19.
Hot Start Lever Freeplay
left handlebar
(1) hot start lever
(2) hot start lever freeplay
Inspection
Check freeplay:
1/16 – 1/8 in (2 – 3 mm)
If necessary, adjust to the specified range.Adjustment
Adjustments can be made with the cable end
adjuster.
Loosen the lock nut (3) and turn the adjuster (4).
Turning the adjuster clockwise (+) will increase
free play and turning it counterclockwise (–) will
decrease free play. After adjustment, tighten the
lock nut.
(3)  lock nut (+)  increase
(4)  cable adjuster (–)  decrease
(1)(2)
(4)
(–)
(+)
(3) 
						

							Refer to Safety Precautionson page 19.
Spark Plug Recommendation
The recommended standard spark plug is 
satisfactory for most racing conditions.  
Use only the recommended type of spark plugs in
the recommended heat range.
Using a spark plug with an improper heat range
or incorrect reach can cause engine damage.
Using a non-resistor spark plug may cause 
ignition problems.
This motorcycle uses a spark plug that has an
iridium tip in the center electrode and a platinum
tip in the side the electrode .
Be sure to observe the following when servicing
the spark plug.
• Do not clean the spark plug. If an electrode is
contaminated with accumulated objects or
dirt, replace the spark plug with a new one.
• Use only a “wire-type feeler gauge” to check
the spark plug if necessary. To prevent
damaging the iridium tip of the center
electrode and platinum tip of the side
electrode, never use a “leaf-type feeler
gauge’’.
• Do not adjust the spark plug gap. If the gap is
out of specification, replace the spark plug
with a new one.
NOTICE
54Servicing Your Honda
Spark Plug
Spark Plug Replacement & Inspection
Refer to Safety Precautionson page 19.
1. Remove the seat and fuel tank (pages 29,30).
2. Disconnect the spark plug cap (1).
3. Clean any dirt from around the spark plug bases.
4. Remove the spark plug (2).7.  To obtain accurate spark plug readings,
accelerate up to speed on a straightaway. Push
the engine stop button and disengage the
clutch by pulling the lever in. 
Coast to a stop, then remove and inspect the
spark plug. The porcelain insulator around the
center electrode should appear tan or medium
gray. 
If youre using a new plug, ride for at least ten
minutes before taking a plug reading; a brand-new
plug will not color initially.
If the electrodes appear burnt, or the insulator is
white or light gray (lean) or the electrodes and
insulator are black or fouled (rich), there is a
problem elsewhere (page 122).
Check the carburetor, fuel system and ignition
timing.
8. Tighten the spark plug
If the old plug is good:
1/8 turn after it seats.
If installing a new plug, tighten it twice to
prevent loosening:
a) First, tighten the plug:
NGK: 1/2 turn after it seats. 
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats.
9.  Connect the spark plug cap.
(1) spark plug cap
(2) spark plug
5. Check the electrode for wear or deposits, the
gasket (3) for damage, and the insulator for
cracks. Replace if you detect them.
6.  Check the spark plug gap (4), using a wire-type
feeler gauge. If the gap is out of specifications,
replace the plug with a new one.
The recommended spark plug gap is:
0.024 – 0.028 in (0.6 – 0.7 mm)
(3) sealing gasket
(4) spark plug gap
(1)
(2)
(3)
(4)
Standard
For extend high
speed ridingR0409B-8 (NGK)
R0409B-9 (NGK)
10. Install the fuel tank and seat (page 31). 
						

							Servicing Your Honda55
Valve Clearance
Cylinder Head Cover Removal
Before inspection, clean the engine thoroughly to
keep dirt from entering the engine.
1. Remove the seat (page 29).
2. Remove the fuel tank (page 30).
3. Disconnect the breather tube (1) and spark
plug cap (2).
Positioning At Top Dead Center On The
Compression Stroke.
1. Remove the crankshaft hole cap (1).
(1) breather tube (2) spark plug cap
4. Remove the cylinder head cover bolts (3), and
cylinder head cover (4).
(3) cylinder head cover bolts
(4) cylinder head cover(1) crankshaft hole cap
2. Remove the spark plug (2).
(2) spark plug
(2)
(1)
(4)
(3)
(1)
(2)
(cont’d) Refer to 
Safety Precautionson page 19.
Excessive valve clearance will cause noise and
eventual engine damage. Little or no clearance
will prevent the valve from closing and cause
valve damage and power loss. Check the valve
clearance when the engine is cold at the intervals
specified in the Maintenance Schedule.
The checking or adjusting of the clearance should
be performed while the engine is cold.
The clearance will change as engine temperature
rises. 
						

							Valve Clearance
56Servicing Your Honda
Valve Clearance Inspection
1. Measure the intake valve clearance by
inserting a feeler gauge (1) between the valve
lifters (2) and intake cam lobe (3).2. Measure the exhaust valve clearance by
inserting a feeler gauge (1) between the
exhaust rocker arm (4) and shim (5).
(1) feeler gauge
(4) exhaust rocker arm
(5) exhaust valve shim
Valve Clearances:
IN:  
0.005 ± 0.001 in (0.12 ± 0.03 mm)
EX: 0.011 ± 0.001 in (0.28 ± 0.03 mm)
If intake valve clearance and exhaust valve
clearance need adjustment, see 
Camshaft
Removal
(page 57) and select the correct shim for
each valve.
(6)
(1)
(3)
(2)
(1)
(5)(4)
(1)  feeler gauge
(2)  valve lifters
(3)  intake cam lobe
3. Rotate the crankshaft by turning the primary
drive gear lock bolt (3) (crankshaft) clockwise
until aligning the “punch” mark (4) on the
primary drive gear with the index mark (5) on
the right crankcase cover. In this position, the
piston may either be on the compression or
exhaust stroke.
If the crankshaft passed the “punch” mark,
rotate the primary drive gear lock bolt
clockwise again and align the “punch” mark
with the index mark.
The inspection must be made when the piston
is at the top of the compression stroke when
both the intake and exhaust valves are closed.
This condition can be determined by moving
the exhaust rocker arm (6). If it is free, it is an
indication that the valves are closed and that
the piston is on the compression stroke. If it is
tight and the valves are open, rotate the
primary drive gear lock bolt 360°and realign
the “punch” mark to the index mark.
(3)(5)
(4)
(3) primary drive gear lock bolt (5) index mark
(4) “punch” mark
(6) exhaust rocker arm