The 2 Stroke Dirt Bike Engine – Review of the Good and Bad earns a small commission from qualifying purchases.
This does NOT cost you extra.

Dirt bike motors are impressive, to say the least. They tend to last a decent amount of time as long as you keep up on regular the maintenance like cleaning and oiling the air filter, changing the oil, and so on. However, there is quite a difference between 2 stroke and 4 stroke dirt bike engines.

In this article, we will look at the 2 stroke dirt bike engine, some of it’s strengths, some of it’s weaknesses, and how it works.

2 Stroke Dirt Bike Engine

Strengths of the 2 Stroke Motor

Currently, Yamaha is one of only a few companies still producing 2 stroke dirt bikes like the YZ250. Which is sad because the stroke engine – at least 2 stroke dirt bike engines – are quite impressive. Two strokes are known for a few things:

  • Loud
  • Smelly
  • Powerful
  • Light

Of course, there are more characteristics that accompany the engine, but those are the well known ones. And, as you probably figured out for yourself, some of those characteristics are good, and some are not.

NOTE: It’s not a good thing if you get water inside your two stroke’s engine. That’s why I always recommend using a quality exhaust plug whenever washing your bike.

A 2 stroke engine has fewer mechanical parts than a 4 stroke engine. This makes for a significant reduction in weight when compared to the 4 stroke engine, but certainly no loss in power… which is why you see chain saws, weed eaters, jet skis, and other tools and toys utilizing them.

In addition to producing a more impressive weight-to-power ratio, 2 strokes are also cheaper and easier to work on.

How 2 Stroke Dirt Bike Engines Work

The 2 stroke engine is fairly simple – as far as engines go. The motor has two primary functions that make it work:

  1. Compression
  2. Combustion

Basically, the spark plugs are ignited and the engine is fired with each revolution.

As you may already know, the power output of a 2 stroke dirt bike motor is significantly more than that of a 4 stroke motor… basically double. A 250 2 stroke is equivalent to a 450 4 stroke, and a 125 2 stroke is equivalent to a 250 2 stroke.

Related: 2 Stroke VS 4 Stroke Dirt Bike – Which is Better for Beginners & Trail Riding?