Engine Top End Specifications For Your 97-01 Honda CR250 Dirt Bike
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Engine Specifications
| Engine Type | 2-Stroke, Single-Cylinder, Liquid Cooled |
| Engine Intake System | Crankcase Reed Valve |
| Engine Displacement | 249.3cc (15.2ci) |
| Engine Dry Weight | 51.4 lb. (23.3 kg) |
| Bore & Stroke | 66.4 x 72.0 mm (2.61 x 2.83 in) |
| Lubrication | 32:1 Fuel/Oil Premix |
| Compression Ratio | 8.7:1 |
| Crankshaft | Assembly Type |
| Ignition Timing | |
| – 1997 | 18° At 3000 RPM |
| – 1998-2001 | 18° ± 2° At 3000 RPM |
Engine Service Specifications
| New – mm (in.) | Service Limit – mm (in.) | |
| Measurement Point I.D. | ||
| – Size A Cylinder | 66.398-66.405 (2.6141-2.6144) | 66.430 (2.615) |
| – Size B Cylinder | 66.390-66.398 (2.6138-2.6141) | 66.428 (2.615) |
| Cylinder Warp Limit | – | 0.05 (0.002) |
| Cylinder Taper Limit | – | 0.05 (0.002) |
| Cylinder Out Of Round Limit | – | 0.05 (0.002) |
| Cylinder Head Warp Limit | – | 0.05 (0.002) |
| Piston | ||
| O.D. Measurement Point | 15-20 (0.59-0.95) From Skirt Bottom | |
| – O.D. Size A Piston | 66.330-66.338 (2.6114-26.117) | 66.28 (2.609) |
| – O.D. Size B Piston | 66.323-66.330 (2.6111-2.6114) | 66.273 (2.609) |
| Piston-To-Cylinder Clearance | 0.060-0.075 (0.0024-0.0029) | 0.09 (0.004) |
| Piston Pin Bore I.D. | 18.007-18.013 (0.7089-0.792) | 18.02 (0.709) |
| Piston Pin O.D. | 17.994-18.000 (0.7084-0.7087) | 17.98 (0.707) |
| Piston Pin-To-Piston Clearance | 0.007-0.019 (0.0003-0.0007) | 0.04 (0.0016) |
| Piston Ring-to-ring Groove Clearance | ||
| – Top Ring | 0.045-0.075 (0.002-0.003) | 0.095 (0.0037) |
| – Second Ring | 0.025-0.055 (0.001-0.002) | 0.075 (0.026) |
| Piston Ring End Gap | 0.40-0.55 (0.016-0.022) | 0.65 (0.026) |
| Piston Mark Direction | IN Facing Intake Side | |
| Connecting Rod Small End I.D. | 21.997-22.009 (0.8660-0.8665) | 22.02 (0.867) |
| Exhaust Valve Shaft O.D. | 4.988-5.000 (0.1964-0.1969) | 4.968 (0.196) |
Engine Torque Specifications
| N•n | in.-lb. | ft.-lb. | |
| Cylinder Mounting Nuts | 39 | – | 29 |
| Cylinder Head Nuts | 27 | – | 20 |
| Cylinder Stud Bolts | 12 | 106 | – |
| Cylinder Cover Bolts (Right) | 10 | 88 | – |
| Engine Upper Mounting Nut | |||
| – 1997-1999 | 39 | – | 29 |
| – 2000-2001 | 54 | – | 40 |
| Engine Lower Mounting Nuts | |||
| – 1997-1998 | 39 | – | 29 |
| – 1999 | 64 | – | 47 |
| – 2000-2001 | 54 | – | 40 |
| Engine Hanger Plate Nuts | 26 | – | 20 |
| Engine Stop Button Screw | 1.5 | 13 | – |
| Exhaust Front Chamber Bolt | |||
| – 1998-1999 | 10 | 88 | – |
| – 2000 | 12 | 106 | – |
| – 2001 | 14 | – | 10 |
| Exhaust Valve Cap (Left) | 13 | 115 | – |
| Exhaust Valve Stopper Bolt | 16 | – | – |
| Exhaust Valve Linkage Allen Bolt | 5.4 | 48 | – |
| Exhaust Valve Pinion Holder Allen Bolt | 5.4 | 48 | – |
| Spark Plug | 18 | – | 13 |
Keep Your ’97-’01 CR250 Running Right!
