Chainsaw Parts

Chainsaw power head or engine

Chainsaws use a two stroke engine which has certain advantages.
The two stroke engine has no valves and fires on every revolution unlike a four stroke which fires on every second revolution. This results in a power to weight ratio being twice the power in the same space when compared to a four stroke.

Another advantage is a two stroke is lubricated from oil mixed with the fuel so unlike a four stroke operating on its side or upside down is not a problem.

Picture of Clutch

Chainsaw clutch

This powerful light weight engine is linked to the cutting chain by a centrifugal clutch. This clutch is disengaged at an idle and as the rpm increases the clutch will engage. It operates similar to an automatic transmission in a car.

Chainsaw Chain

The chainsaw chain is made of steel and consists of a series of cutters on the top or outside and drive links on the bottom or inside and side plates joined together by a rivet process.

Chainsaw Bars

Chainsaw bars come in many different lengths and sizes designed to match a corresponding power head. The bar is basically a long slim blade with a groove for the chain to ride in. At the tip there is a freewheeling type of gear to reduce friction and wear and tear. The chain forms a continuous loop around the clutch and drive sprocket at the power head and out around the tip of the bar. The chain tension is adjustable and there is a constant supply of special oil injected at the power head into the bar groove which is carried around the bar by the chain keeping it lubricated.

The bar should be removed and flipped over approx every 10hrs of operation to allow for both sides to wear equally. When you have your bar removed clear the bar groove of any built up dirt, a putty knife or similar will work Also make sure the small oil holes at the sprocket end are clear, a piece of small haywire or similar will work.  

Chainsaw Drive Sprocket

Drive sprockets should be replaced with a new one about every two chains you go through. When the sprocket is worn badly it will damage the drive links of your chain.