CRANKSHAFT/BALANCER. Honda CBR125R

CRANKSHAFT/BALANCER/TRANSMISSION

CRANKSHAFT/BALANCER

REMOVAL

Separate the crankcase halves (page 12-6).

Remove the crankshaft and balancer assembly from the right crankcase.

CRANKSHAFT

CRANKSHAFT INSPECTION

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.

SERVICE LIMIT: 0.03 mm (0.001 in)

BALANCER ASSEMBLY

BIG END SIDE CLEARANCE

Measure the side clearance of the connecting rod big end with a feeler gauge.

SERVICE LIMIT: 0.85 mm (0.033 in)

58.0 mm (2.28 in) 56.5 mm (2.22 in)

12-8

CRANKSHAFT/BALANCER/TRANSMISSION

BIG END RADIAL CLEARANCE

Measure the radial clearance of the connecting rod big end.

SERVICE LIMIT: 0.05 mm (0.002 in)

If the timing sprocket teeth are worn or damaged, check the cam chain, tensioner and cam sprocket.

TIMING SPROCKET

Check the timing sprocket teeth for wear or damage.

If you are replacing the timing sprocket, align the center of the sprocket teeth with the center of the woodruff key groove as shown.

TIMING SPROCKET

RIGHT SIDE:

CRANKSHAFT BEARING

Turn the inner race of the right crankshaft bearing with your finger.

The bearing should turn smoothly and quietly.

Also check that the outer race fits tightly in the crankcase.

LEFT SIDE: Turn the outer race of the left crankshaft bearing with your finger.

The bearing should turn smoothly and quietly.

Also check that the inner race fits tightly on the crankshaft.

Replace the bearing in pairs.

Remove and discard the bearing if the races do not turn smoothly, quietly, or if they fit loosely in the crankcase and crankshaft.

For crankshaft bearing replacement (page 12-18).

LEFT SIDE shown:

BALANCER BEARING

Turn the inner race of the right crankshaft bearing with your finger.

The bearing should turn smoothly and quietly.

Also check that the outer race fits tightly in the crankcase.

Remove and discard the bearing if the races do not turn smoothly, quietly, or if they fit loosely in the crankcase and crankshaft.

For balancer bearing replacement (page 12-19).

GROOVE

12-9

CRANKSHAFT/BALANCER/TRANSMISSION

BALANCER DISASSEMBLY

If you replace the balancer driven gear, be careful to select the identification color of the balancer driven

gear (page 12-11).

Remove the following:

– Snap ring

– Thrust spring

– Washer

WASHER

Remove the balancer damper rubbers, balancer gear springs and balancer driven gear.

Check the rubbers and springs for damage, replace it if necessary.

THRUST SPRING SNAP RING

SPRINGS

Check the balancer driven gear for excessive or damage, replace it if necessary.

RUBBERS BALANCER DRIVEN GEAR

12-10

BALANCER ASSEMBLY

Apply molybdenum oil solution to the balancer driven gear inner surface.

Install the balancer driven gear, balancer gear springs and balancer damper rubbers.

SPRINGS

RUBBERS BALANCER DRIVEN GEAR

Make sure the snap ring is firmly seated in the groove.

Install the following:

– Washer

– Thrust spring

– Snap ring

CRANKSHAFT/BALANCER/TRANSMISSION

WASHER

SNAP RING

BALANCER DRIVEN GEAR SELECTION

The balancer driven gear has ID color.

BALANCER DRIVEN GEAR SELECTION TABLE

ID COLOR

WHITE

BLUE

YELLOW

P/N

13422-KPP-860

13423-KPP-860

13424-KPP-860

If the balancer driven gear is replaced with a new one, select the same colored gear as the original gear.

If the crankcase is replaced a new one, select the blue marked gear.

BALANCER DRIVEN GEAR

INSTALLATION

Engage the balancer assembly and crankshaft by aligning the two punch marks on the balancer driven gear and crank weight as shown.

THRUST SPRING

ID COLOR

PUNCH MARKS

Be careful not to out of alignment.

Install the crankshaft and balancer assembly together into the right crankcase.

CRANKSHAFT

BALANCER ASSEMBLY

12-11