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Harley Davidson Motorcycles Service Center Fullerton Orange County California at Motorhelmets

Spark the Fire: A Guide to Metric Cruiser & Harley Davidson Spark Plug Replacement

Understanding Spark Plugs:

  • Spark plugs are small but mighty components responsible for igniting the air-fuel mixture within your engine's cylinders. Over time, their electrodes wear down, reducing their ability to generate a strong spark, leading to various performance issues.

Signs of Faulty Spark Plugs:

  • Difficulty starting: The engine struggles to crank or stalls frequently due to weak spark.
  • Reduced power and performance: Worn plugs hinder efficient combustion, leading to sluggish acceleration and lower power output.
  • Engine hesitation and surging: Erratic spark delivery causes the engine to sputter and surge inconsistently.
  • Increased fuel consumption: Incomplete combustion due to weak spark translates to poorer fuel efficiency.

Choosing the Right Spark Plugs:

  • Not all spark plugs are created equal. Choosing the right type for your specific motorcycle model is crucial for optimal performance and lifespan. Consider these factors:
    • Heat range: Refers to the spark plug's ability to dissipate heat. Choose the correct heat range based on your engine type and riding style.
    • Electrode material: Different materials offer various benefits, such as improved ignitability or longer lifespan. Consult your owner's manual or a trusted mechanic for recommendations.

The Cost Equation:

  • Spark plug replacement costs vary depending on the number of cylinders in your motorcycle, the type of spark plugs chosen, and the shop's labor rates:
    • Spark Plugs (Varies): $150.00 - $400.00

DIY or Pro?

  • While replacing spark plugs might seem straightforward, consider these factors:
    • Accessibility: Spark plugs on some motorcycles, particularly Harley Davidsons, can be difficult to reach, requiring specialized tools and knowledge.
    • Torque specifications: Over-tightening or under-tightening spark plugs can damage the engine.
    • Identifying the correct plugs: Choosing the wrong type of spark plug can lead to performance issues and engine damage.

Beyond the Replacement:

  • Maintaining optimal spark plug performance involves additional practices:
    • Regular inspections: Check your owner's manual for recommended spark plug replacement intervals and inspect them visually for signs of wear.
    • Use high-quality fuel: Clean fuel burns more efficiently, reducing deposits on spark plug electrodes.
    • Avoid short rides: Frequent short trips prevent the engine from reaching optimal operating temperature, which can accelerate spark plug wear.

Ride with Confidence, Not Sputters:

  • By understanding the importance of spark plug replacement, their costs, and valuable tips, you can keep your metric cruiser or Harley Davidson running smoothly and efficiently. Remember, timely spark plug changes are an investment in your motorcycle's performance, fuel economy, and ultimately, your worry-free riding enjoyment. So, don't let worn-out spark plugs dim your riding experience – schedule a replacement service today and reignite the fire in your motorcycle's engine!

Bonus Tip:

  • Consult your motorcycle's owner's manual for specific spark plug recommendations, replacement intervals, and torque specifications based on your model.

Motorhelmets Metric Cruiser / Harley Davidson Spark Plugs (Varies) Services

Service Description:

  • Spark Plugs (Varies) Services

When to Perform the Service:

  • Spark plug replacement is recommended as part of regular maintenance or when the spark plugs show signs of wear, such as fouling or erosion.
  • It's also advisable to replace spark plugs if the motorcycle experiences starting difficulties, misfires, or poor engine performance.


  • Spark plug replacement mileage varies depending on the motorcycle model, manufacturer recommendations, and usage conditions.
  • It's generally recommended to inspect and, if necessary, replace spark plugs every 10,000 to 20,000 miles.


  • Spark Plugs (Varies) Services: $150.00 - $400.00


  • Spark plugs play a crucial role in the ignition system, providing the spark necessary to ignite the air-fuel mixture in the engine combustion chamber.
  • Regular replacement of spark plugs ensures optimal engine performance, fuel efficiency, and reliable starting.
  • Faulty or worn spark plugs can lead to poor engine performance, misfires, decreased fuel economy, and potential engine damage.

For More Information - Contact Us


Motorhelmets Fullerton CA

1871 W. Commonwealth Ave., Fullerton CA 92833 USA
Tel: 714-879-8180 | Email:
Service Dept SMS Txt: 657-217-3988 | Sales Dept SMS Txt: 657-217-6457
Store Hours: M-F 10am-7pm | Sat 11am-6pm
Schedule My Service | Buy My Service

General HD Service Guideline Below

Maintain regular service on your Harley Davidson motorcycle. Regular intervals is recommended for optimal performance. Service should be at 1,000, 5,000, 10,000, 15,000 and 20,000 Miles. Every 5 thousand miles thereafter.

Harley Davidson Motorcycles Service Center Fullerton Orange County California at Motorhelmets

Harley Davidson Motorcycle Maintenance Suggestions
Simple Self Maintenance Tips between visits to our service shop.

  • Clean the battery terminals, coat with dielectric grease to prevent corrosion
  • Examine pivot points and moving parts for signs of wear/ interference
  • Check the standing voltage at each battery terminal (using a multimeter)
  • Check for failed fork seals and dripping fluid under the bike
  • Check for blown fuses and ensure that spares are present
  • A well maintained Harley Davidson motorcycle with high mileage is always better than a poorly maintained bike with low miles

Harley Davidson Motorcycles Service Center

Fullerton / Orange County California

Service, Repair, Tires, Maintenance

Let our professionals keep your Harley in the best condition

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