How to Tell the Size of a Dirt Bike

by Gary Proulx

Dirt bike engines come in many different sizes. It can sometimes seem confusing, but always remember that most dirt bike engines are designed to fit into a particular size category. This is because dirt bike races are classified by the size of the bike's engine. These races usually have classes such as under 125cc, 125cc, 250cc and open class, which allows the largest engines. This classification system allows racers to remain competitive with each other.

Step 1

Look at the side panels of the motorcycle. Many manufacturers display the engine size as part of the overall paint scheme of the bike. The engine size can also sometimes be displayed on the radiator shroud or the rear swing-arm.

Step 2

Inspect the top of the engine cases. Look for a number ending with "cc." This is always stamped into the upper engine case, usually on the left side. If the number is 250cc, for example, the motorcycle is classified as a 250.

Step 3

Examine the side of the steering neck, which is in front of the gas tank and locate the series of numbers printed there. These numbers are used to identify the exact year and size of the motorcycle. Call up a motorcycle shop and ask them to identify the motorcycle by this series of numbers; any shop can do this.

Step 4

Check the title of the motorcycle. The title will have information about the specific model number, which will indicate the engine size.

Tips & Warnings

  • Remember that small motorcycles have small components. If the motorcycle is very short or if it has small wheels, it will have a small engine.
  • If inspecting a bike before buying, never purchase it if any of the engine or frame numbers have been removed; this indicates that the bike is probably stolen.
  • When looking at the title, be certain that it matches the frame number before buying the bike.


About the Author

Gary Proulx has been writing since 1980. He specializes in automotive technology and gasoline and diesel design. Proulx has had multiple articles published on various websites. He is also an archery expert who writes about the ins and outs of archery as a sport.

Photo Credits

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