Honda Valve Adjustment Service
The importance of correct Honda valve adjustment can’t be over-stressed, as it can directly effect the performance and life of the engine.
Valves are opened by camshaft lobes on overhead camshaft engines and by rocker arms on pushrod engines. With extended time and use, the original clearances between these parts and the valve stems become bigger (with exhaust valves, the clearance can become tighter over time). That often leads to a clattering noise or more engine vibration that a driver might not notice for quite a while, because it increases gradually.
Intake valves open and close to let the air-fuel mixture (or just air in some modern engines) enter the combustion chambers, and the exhaust valves allow exhaust gases to escape. Too much or too little valve clearance can result in poor performance or a rough idle because the engine can’t “breathe” normally and operate at peak efficiency. Too much clearance means the valves will likely clatter and, over the long term, cause damage to the valves and/or camshaft lobes or rocker arms. If there’s too little clearance the valves won’t fully close, causing excessive heat, and the engine will lose power.
If your engine generates a loud clatter, it could be time for a valve clearance adjustment — though on some engines the valves don’t generate noise when there’s too much clearance. Loss of power could be a sign of a weak or broken valve spring, and a tapping noise could be caused by a loose rocker arm, so a clearance adjustment may not be all that’s needed.
By ensuring that you have your Honda valves adjusted at the factory recommended mileage intervals will help to prevent premature engine failure and costly repairs, and can help to ensure that your engine is running efficiently and quietly for a long time.