Any motorcycle owner knows how important routine maintenance is for their bike. Regular servicing is important to ensure it’s running optimally, staying on top of general wear-and-tear, and preventing any issues.

When it comes to routine maintenance, it’s particularly important to pay attention to the motorcycle’s engine and valves. If a motorcycle’s valve is having issues, it can impact engine power and, in severe cases, even lead to engine damage.

The Different Motorcycle Valves

Motorcycle valves

Valves play an important role in motorcycle engines. It’s the component that helps regulate fuel and airflow throughout the engine’s combustion changer. Typically, a motorcycle has two types of valves:

  • Intake valves
  • Exhaust valves

The intake valve opens to allow air and fuel to enter the combustion chamber. The exhaust valve opens to allow exhaust gases to exit the combustion chamber after the combustion process is complete.

Both valves operate on a camshaft, which is synchronised with the rotation of the engine’s crankshaft. They’re both integral to the function of the motorcycle’s engine, which is why it’s essential to get them regularly maintained and cleaned.

For instance, valves need to be adjusted to ensure they open and close at the correct intervals to let in air and fuel and let out any exhaust gases. If the intake and exhaust valves aren’t adjusted correctly, it could lead to reduced engine performance or worse.

Valves also play an important role in braking. When the throttle closes on your bike, the intake valves close, and the engine’s momentum causes the pistons to compress the air and fuel mixture—creating resistance that, along with braking, causes the motorcycle to slow down.

What Are The Symptoms of Bad Motorcycle Valves

Motorcycle valves

If a motorcycle has a bad valve or needs an adjustment, there are signs. The following are just a few symptoms that might mean your motorcycle requires an adjustment or repair.

  • Difficulty starting the motorcycle.
  • Backfiring or misfiring, especially during acceleration or deceleration.
  • The engine is overheating.
  • Excessive vibration when riding.
  • Ticking or tapping noise.
  • Loss of power and performance—the engine might feel sluggish.
  • Excessive smoke coming from the exhaust.

Adjusting Motorcycle Valves

Motorcycle valves

Valve adjustment is an important maintenance procedure to ensure your motorcycle is running optimally and ensuring the valve is operating correctly. Before delving into valve adjustment, it’s important to understand what valve clearance (sometimes referred to as lash) is.

Valve clearance refers to the gap between the rocker arm and the valve or camshaft that opens and closes the valve.  For motorcycles, it’s critical that the valve clearance is adjusted so the valve opens and closes at the correct time with the proper amount of life.

If the valve clearance is incorrect, it can lead to various issues. These include reduced power, poor fuel economy, increased emissions and, in severe cases, engine damage.

Valve clearance can change over time due to general wear and tear. That’s why it’s essential to regularly check your valve lash and adjust it when needed. 

How often do you adjust motorcycle valves? 

The frequency at which you should adjust and check the valves on your motorcycle will depend on the make and model, how much you ride, and the type of engine. We recommend the manufacturer’s recommended maintenance schedule if you have a manual.

As a general rule of thumb, most motorcycles require a valve adjustment at least every 20,000 to 25,000 kilometres or every 2-3 years, whichever comes first. It’s also important to note that some bikes may use hydraulic valve lifters or parts that don’t require regular valve adjustments.

How to adjust motorcycle valves

Adjusting the valves on a motorcycle requires mechanical experience and skill. It’s a procedure that is typically recommended to be performed by a professional mechanic, especially if you aren’t familiar with the inner workings of a motorcycle engine. However, if you’re confident in your abilities and performing valve maintenance, here is the process to perform an adjustment.

  1. Check your motorcycle’s owner manual for instructions on accessing the valve train and adjusting the valves.
  2. Typically, to access the valve train, you will need to remove the fuel tank, cylinder head cover, and other components.
  3. Before inspecting the valve clearance, it’s important to let your engine cool down—hot components can cause injury.
  4. If you haven’t already, you’ll have to remove the seat and fuel tank to access the valve cover.
  5. Remove the valve cover using the appropriate tools. Depending on the bike, you may also need to remove other components.
  6. After removing the cover, locate the camshaft and rocker arms, as well as loosen the nut on the lock nut or camshaft adjuster screw.
  7. Identify the intake and exhaust valves in the engine.
  8. Using a feeler gauge, check the valve clearance by sliding it between the rocker arm and the valve—the gauge should slide in with a slight resistance.
  9. If the valve clearance is too tight, you want to loosen the lock nut on the adjuster screw and turn it until the clearance is correct.
  10. If the clearance is too loose, tighten the lock nut until it is the correct clearance.
  11. It’s important to use a screwdriver or wrench to turn the adjuster screw until the valve lash is within the manufacturer’s recommended specifications.
  12. After getting the valve clearance to the ideal level, you want to secure the adjustment.
  13. Repeat this process for each valve, and once all valves have been adjusted, reassemble any components removed to access the valve train.
  14. Start the engine and listen for any unusual noises. If necessary, recheck the valve clearance and make further adjustments.

The above steps are just a general guide to adjusting valves; the specific process will depend on the exact make and model. 

Adjusting valves is also a complex procedure that requires specialised skill, knowledge, and tools—so if you aren’t experienced, it’s important to get a professional for safety and accuracy.

Cleaning Motorcycle Valves

If you’re wondering how to clean a motorcycle valve because of build-up, we’ve got you covered—there are a few methods. The first option is to go to a professional shop to get it cleaned, as proper cleaning typically requires disassembly.

The second option is to remove the valves yourself; however, mechanical skill and expertise are required. Once the valves are removed, you can try to scrape off as much of the build-up as possible and walnut shell blasting. 

The third option is to start adding ‘Sea Foam’ to your fuel. Sea Foam is a product for motorcycles that adds protective lubricity to the engine and fuel system and prevents any potential build-up in the valves. It also doesn’t require disassembly.

Book Your Motorcycle in for Routine Maintenance at Taverner Motorsports

Motorcycle valves

If you don’t have the time or space for routine servicing, the team here at Taverner Motorsports can take care of it for you. Whether you need regular maintenance or a comprehensive evaluation, our team works with classic motorcycles, particularly Harley Davidson and British brands.

With over 50 years in the industry, you can trust our mechanics with your bike—whether it’s working on your valve, giving it a clean, or other general maintenance.

The minor and major servicing packages we offer are designed to address the key maintenance requirements of your motorcycle and keep your bike running at its best. Our skilled technicians will ensure your vehicle, including the engine and valves, are working optimally.

For regular maintenance and servicing, get in touch with the Taverner Motorsports team today. You can request a quote online or give us a call.