2009-2010 Honda CRF450R Cylinder Head / Valve Specifications

Aug 2, 2017

170

Cylinder Head & Valve Specifications For Your 2009 – 2010 Honda CRF450R Dirt Bike

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Part	Standard (mm)	Service Limit (mm)
Cylinder Compression	57 psi (392 kPa, 4.0 kgf/cm2) @ 600 RPM	–
Cylinder Head Warpage		0.05
Valve and Valve Guide
Valve Clearance
– IN	0.16 ± 0.03	–
– EX	0.28 ± 0.03	–
Valve Stem O.D.
– IN	4.975 – 4.990	–
– EX	4.965 – 4.980	4.96
Valve Guide I.D
– IN	5.000 – 5.012	5.052
– EX	5.000 – 5.012	5.052
Stem To Guide Clearance
– IN	0.010 – 0.037	–
– EX	0.020 – 0.047	–
Valve Guide Projection Above Cylinder Head
– IN	14.8 – 15.0	–
– EX	17.8 – 18.0	–
Valve Seat Width
– IN	1.1 – 1.3	2.0
– EX	1.3 – 1.5	2.0
Valve Spring Free Length
– IN	40.72	40.6
– EX	42.30	42.1
Rocker Arm
– Rocker Arm I.D.	12.000 – 12.018	12.025
– Rocker Arm Shaft O.D.	11.977 – 11.985	11.97
– Rocker Arm-to-Shaft Clearance	0.015 – 0.041	0.055
Camshaft
Cam Lobe Height
– IN	37.540 – 37.780	37.52
– EX	28.598 – 28.838	28.58
Valve Lifter O.D.	25.978 – 25.993	25.97
Valve Lifter Bore I.D.	26.010 – 26.026	62.04

Keep Your ’09-’10 CRF450r Running Right!