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!
- Service Specifications
- Clutch Replacement
- Fuel System Service
- Engine Top End
- Brakes
- Exhaust
- Front Suspension & Steering
- Rear Suspension
- Wheels & Tires
- Kickstarter
- External Shift Linkage
