Camshaft Inspection (R18A)

Camshaft Inspection

1.Remove the camshaft sprocket.

2.Remove the rocker arm assembly.

3.Put the rocker shaft holders on the cylinder head, then tighten the bolts, in sequence, to the specified torque.

Specified Torque 
6 x 1.0 mm
15 N·m (1.5 kgf·m, 11 lbf·ft)
 

 

4.Seat the camshaft by pushing it toward the rear of the cylinder head.

5.Zero the dial indicator against the end of the camshaft. Push the camshaft back and forth, and read the end play. If the end play is beyond the service limit, replace the thrust cover and recheck. If it is still beyond the service limit, replace the camshaft.

Camshaft End Play 
Standard (New): 0.050-0.250 mm
(0.002-0.010 in.)
 
Service Limit: 0.4 mm (0.02 in.) 

 

6.Remove the camshaft.

7.Wipe the camshaft clean, then inspect the lift ramps. Replace the camshaft if any lobes are pitted, scored, or excessively worn.

8.Measure the diameter of each camshaft journal.

 

9.Zero the gauge to the journal diameter.

 

10.Clean the camshaft bearing surfaces in the cylinder head. Measure the inside diameter of each camshaft bearing surface, and check for an out-of-round condition.

  • If the camshaft-to-holder clearance is within limits, go to 12.
  • If the camshaft-to-holder clearance is beyond the service limit, and the camshaft has been replaced, replace the cylinder head.
  • If the camshaft-to-holder clearance is beyond the service limit, and the camshaft has not been replaced, go to 11.

Camshaft-to-Holder Oil Clearance
Standard (New): 0.045-0.084 mm
(0.0018-0.0033 in.)
 
Service Limit: 0.15 mm (0.006 in.) 

 

11.Check the total runout with the camshaft supported on V-blocks.

  • If the total runout of the camshaft is within the service limit, replace the cylinder head.
  • If the total runout is beyond the service limit, replace the camshaft, and recheck the oil clearance. If the oil clearance is still out of tolerance, replace the cylinder head.

Camshaft Total Runout
Standard (New): 0.03 mm (0.001 in.) max. 
Service Limit: 0.04 mm (0.002 in.) 

 

12.Measure cam lobe height.

Cam Lobe Height Standard (New):
 INTAKE EXHAUST 
PRI 35.754 mm
(1.4076 in.) 
35.813 mm
(1.4100 in.) 
SEC A 35.358 mm
(1.3920 in.) 
SEC B 36.027 mm
(1.4184 in.) 

PRI: Primary SEC: Secondary IN: Intake 
EX: Exhaust C/C: Cam Chain