Valve clearance, or valve lash, is not a single number across all Honda engines. The correct intake and exhaust lash depend on the exact engine family, model, and year. In practice, you must consult the official service manual for your model to obtain the precise cold clearance values for both intake and exhaust valves.
Honda uses different specifications for cars, motorcycles, and small engines, and the difference between cold and hot measurements, as well as metric vs imperial units, can affect what you read on the spec sheet. This article explains why the spec varies and where to locate the correct numbers for your Honda vehicle or equipment.
Where to find the official valve clearance specs for Honda engines
Before we list the general landscape, keep in mind that the exact lash numbers are published by Honda for each engine family and model year. They appear in the engine section of the factory service manual, and sometimes in dealer bulletins or owner resources. The values are typically issued as cold (at room temperature) clearance for both intake and exhaust, and may specify tolerances if the measurement is off by a certain amount.
- Car engines (Honda Civic, Accord, CR-V, etc.): Specs are engine-family specific and shown in the service manual under Valve clearance. They distinguish intake vs exhaust and sometimes specify the measurement in mm or inches, with cold lash as the standard reference.
- Motorcycle engines (CBR, Africa Twin, Rebel, etc.): Each model year and engine family has its own lash spec in the official manual or service information. Expect separate intake and exhaust values in metric or inch units.
- Small engines and power equipment (GX series, lawn equipment, generators): The official manuals list the lash values and measuring method; these often use metric units and emphasize cold measurements.
While this section outlines where to locate the numbers, the exact specification will be in your model’s service manual. Always verify with the original manufacturer documentation before performing any adjustment.
How to measure and adjust valve clearance (cold lash)
Measuring valve clearance safely requires proper tools and technique. Below is a general guide; always follow the specific service manual for your engine to avoid damage.
- Prepare the engine: ensure it is completely cool, disconnect the battery (for electrical systems), and remove the valve cover to access the cam lobes and tappets.
- Rotate the engine to bring the correct cylinder's cam lobe at zero degrees (TDC on the compression stroke) for the valve you are measuring. This ensures the valve is fully closed.
- Use a feeler gauge to check the gap between the cam follower/rocker and the valve stem according to the intake or exhaust specification. Try several gauge sizes as needed to find the correct clearance within tolerance.
- If the clearance is outside spec, adjust as per the service manual: loosen the locknut on the adjuster screw (if it's an adjustable bucket or shimless design), re-shim or reposition the rocker/adjuster to obtain the correct lash. For many Honda engines with adjustable cam/rockers, you’ll remove the cam cover, loosen the adjuster, and set lash to the target value with a feeler gauge.
- Recheck both intake and exhaust clearances after adjustment, reinstall the valve cover, reconnect the battery, and start the engine to listen for normal operation. If there are unusual noises, shut down and recheck the lash.
Doing valve clearance work can affect engine timing and reliability. If you are not comfortable performing these steps or lack the right tools, seek a professional mechanic or a Honda-certified technician.
Note on units and terminology
Some Honda manuals list lash in millimeters (mm) while others list them in thousandths of an inch (in). If you are not sure which unit your manual uses, check the front matter of the manual or the valve clearance table to confirm. The critical point is to use the spec exactly as published for your engine.
Summary
Valve clearance values for Honda engines are not universal. The correct intake and exhaust lash depend on the engine family, model year, and whether the measurement is cold or hot. To obtain the precise specifications, consult the official service manual for your specific Honda model and engine, and follow the recommended procedure for measuring and adjusting lash. When in doubt, contact a Honda-certified technician to ensure the engine remains reliable and performs to spec.