Do you know what all the parts in a cylinder kit do?

Niche Industries Standard Bore Cylinder Kit for the Yamaha PW50/QT50Niche Industries Standard Bore Cylinder Kit for the Yamaha PW50/QT50 ~ MSRP $295.65 USD. Save more than 70% at Click the image for more information.

Cylinder kits come with many parts to help rebuild your top end or increase your machine's performance. But do you know what each part does?

To better understand all the parts of a cylinder kit and their functions, we'll use the Niche Industries Standard Bore Cylinder Kit for the Yamaha PW50/QT50 as an example. Please note that the Yamaha PW50 has a two-stroke engine and some of the parts or their functions may relate only to two-stroke engines. The Cylinder houses the piston. It's the combustion that occurs inside the cylinder that powers your machine. The Cylinder Head houses the sparkplug and the top of the combustion chamber and sits on top of the cylinder. Between the two is the Head Gasket, which is a piece of thin material (usually metal) that "seals in the internal combustion process" (Bumbeck). Similarly, the Base Gasket seals the cylinder to the crankcase. If you look at the photo above, you can see where the gaskets fit on the cylinder and cylinder head. Lastly, the Cylinder Studs and the Cylinder Stud Nuts attach the cylinder and the cylinder head to the crankcase. Similarly, you can also see where the studs go (though the cylinder head, the gaskets, and the cylinder) in the pictures above.

Inside the cylinder, the Piston transforms "chemical energy contained in the fuel to mechanical energy" (CarsDirect). The piston is connected to the crankshaft which moves the piston inside the cylinder. At the top of the cylinder, the Sparkplug ignites the fuel-air mixture inside the combustion chamber, forcing the piston down. The Piston Wristpin attaches the connecting rod to the piston, while the Piston Rings seal "the edge of the piston and the edge of the cylinder to ensure that none of the force from the explosion escapes around the piston" (CarsDirect). If you look at the photo above, you can see how the piston, piston wristpin, and piston rings fit together.

In between the piston wristpin and the connecting rod, is the Needle Roller Bearing, "a bearing that uses small cylindrical rollers... to reduce friction of a rotating surface" (EngineerLive). It is typically used in two-stroke engines because these bearings do not need much oil to operate (Cameron). Lastly, Circlips are the circular metal rings that hold the piston wristpin within the piston. We include new circlips in our cylinder kits to ensure the perfect fit with your new piston.

Were you able to name all the parts in a cylinder kit?

Curious to see more about the Niche Industries Standard Bore Cylinder Kit for the Yamaha PW50/QT50? See the video below:

Looking for cylinder kits? has cylinder kits for a variety of ATV/UTV models and makes. Click here to see more.


"All the Pistons Parts Explained." CarsDirect. Internet Brands Automotive, 31 October, 2012. Web. 18 August, 2015.

Bumbeck, Mike. "6 steps to changing a head gasket." Mobil. Exxon Mobil Corporation, n.d. Web. 18 August, 2015.

Cameron, Kevin. "Tech Talk: Two-Strokes, Explained." Cycle World. Bonnier Corporation, 6 April, 2015. Web. 21 August, 2015.

"Needle roller bearings: 60 years and still evolving." EngineerLive. Setform Limited, 21 February, 2015. Web. 19 August, 2015.

Big boreCylinderCylinder kitPistonStandard boreYamahaYamaha pw50

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