What Are Air Cut-Off Valves For

Bikers are DIY experts and homegrown mechanics, the elite of garage bargain hunters, priding themselves on finding cheap motorcycle parts that provide them with the form and function they need. However, even in this community of skilled and creative geniuses, you may still find people who have never heard of an air cut-off valve. These valves, nonetheless, are a vital component of the fuel and air intake systems. Therefore, while most motorcycle enthusiasts would prefer to customize their bikes with personality and motorcycle light kits, it pays to understand these necessary and essential engine elements.

Air Blockers

Air cut-off valves, in combination with carburetor O-rings, help to regulate and restrict air flow. This restriction increases the ratio and mixture of fuel and air when decelerating and sliding into lower RPMs. The regulation of air flow and fuel intake allow for smooth transitions and idling with limited or no choking.

Symptoms of Bad Valves

When the valves are good, you will never know they are there. However, over time valves can harden, disintegrate or perforate. When this happens, you will notice that your bike is in a permanent state of low RPMs. Also, you will likely experience one or several other symptoms of failed valves.

• Heavy and prolonged choking to start the engine
• Stalling or hesitation even after warmup
• Frequent backfiring when cruising

Potential Damage to Engine

If you experience any of the symptoms of failed air cut-off valves and choose to do nothing, then you risk severely damaging your engine. Failed valves can lead to any number of engine problems.

• Frequent overheating
• Poor fuel air-ratio
• Damaged gasket heads
• Coolant seepage

If left unchecked or misdiagnosed as an air screw issue, your engine could experience a loss in gas mileage, and you could experience total engine failure. It Is better to be safe than sorry when dealing with any combination of the above issues and check the valves first.

Air cut-off valves are an essential part of your motorcycle engine, helping to regulate and restrict air flow. While not necessarily common knowledge, you should understand these valves to ensure the continued functionality of your bike.

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