How to Maintain a 2-Stroke Dirt Bike

by David Johnston

Though four-stroke dirt bikes have been gaining in popularity, the noisy, blue-smoke emitting two-strokes that dominated the motocross scene for so many years still has many enthusiastic devotees . Two-stroke engine dirt bikes have certain advantages over four-stroke engines such as lighter weight, fewer moving parts and higher horsepower. However, two-stroke engines generally don't last as long as four strokes. It's important to properly maintain a two-stroke engine to get the most use out of it.

Items you will need

  • Two-stroke engine oil
  • Spark plugs
  • Carbon deposit cleaning solvent
  • Air filter oil
Step 1

Always remember to add two-stroke engine oil to your gasoline in the ratio specified with your owner's manual. In a two-stroke engine, the crankcase serves as a pressurization chamber to force fuel and air into the cylinder, and cannot serve as an oil reservoir. If oil isn't added to the gasoline, the engine has no lubrication and will fail quickly.

Step 2

Replace the spark plugs at regular intervals based on how often you ride and your riding style. Spark plugs fire more often in two-stroke engine, placing more wear and tear on them. High-RPM racing will require the spark plugs to be replaced more often.

Step 3

Clean out the carbon deposits on the piston, head and exhaust port. Because oil is added directly into the gasoline in a two-stroke engine, the engine doesn't burn fuel as cleanly as a four-stroke. A proper cleaning will require the engine to be taken apart and cleaned with an anti-carbon deposit solvent. Running the engine at wide-open throttle periodically can also help burn out the deposits. Take necessary safety precautions when running in wide-open throttle.

Step 4

Change the piston and rings periodically. Two-stroke engines place a great deal of stress on the piston and rings due to their rapid combustion rate. Expect to replace these parts about once per year with moderate riding frequency and more often for high-frequency, high-intensity riding.

Step 5

Keep the air filter clean and oiled. The air filter helps keep debris out of your engine. Even very small particulate can cause damage if it makes its way to the engine.


  • Motocross and Off-Road Motorcycle Setup Guide; Mark Thompson; 2010

About the Author

David Johnston works internationally as a freelance writer and editor in a number of professional fields. He received his bachelor’s degree in English from the University of Colorado at Colorado Springs.