Vertex Top End Piston Kit - Yamaha YZ125 YZ125X

Vertex Top End Piston Kit provides everything you need for your top-end rebuild, eliminating the hassle of sourcing components separately. The kit includes an OEM Vertex piston, rings, piston pin, circlips and a top-end gasket kit for an exact fit, and wrist pin bearing (for 2 Strokes). Four-stroke kits include free Camchain!

Kit includes

• Vertex piston
• Piston rings
• wrist
• pin
• circlips
• top-end gasket kit
• 2-stroke applications include wrist pin bearing
• 4-stroke applications include Hot Cams cam chain for a more complete rebuild

Vertex gasket kits

The gasket kit contains all the necessary gaskets to rebuild your top end. Kit includes head, base and exhaust gaskets, as well as O-rings, that are necessary when removing the cylinder and head during routine maintenance.

Replica Cast piston in original OE form

Vertex two-stroke pistons

Because of a cast piston's ability to contain higher silicon content compared to forged pistons, and because twostrokes have lower cylinder pressures when compared to four-strokes, cast pistons are ideal for two-stroke engines. Vertex pistons are gravity cast from an aluminum alloy with 18% silicon content.

Silicon is important because:

• It decreases thermal expansion, which changes thegeometry after the piston reaches operating temperature.With low thermal expansion characteristics, Vertex pistons can be run at tighter tolerances compared with forged pistons. This creates better power and performance, also making them less susceptible to rattling or breaking.
• Silicon gives the pistons better wear characteristics and prolongs piston life by decreasing wear on the piston skirt.

Vertex is a company from Italy which produces original pistons for many currently produced two and four stroke dirtbikes. Their pistons are found in original KTM dirtbikes and their aftermarket range are known as 'Performance Pistons'. Vertex pistons are also popular for high-end tuning.

Technical features of Vertex pistons:

• All pistons are heat treated with a T-5 hardening and tempering cycle
• All piston skirts are coated with a high-tech Molybdenum Disulphite coating for faster break-in time and increased piston life
• Cast piston kits are gravity cast aluminum alloy (not forged) with 18% silicone content, which produces an extremely light but very strong piston
• Forged pistons are forged from 2618 aluminum for superior strength and durability
• Forged High Compression pistons improve power and torque across entire rpm range
• Big Bore pistons increase engines displacement, torque, and peak horsepower
• Forged Replica pistons are forged OE replacements
• Replica pistons and all rings are OEM replacements
• Kits include piston, rings, wrist pin and circlips
• Replacement two-stroke piston rings sold individually; four-stroke piston rings sold as a set

Vertex Produces many different type of pistons. In the overview below you can check the main differences between the dirtbike piston types.

Replica: Cast piston in original OE form

Race: Cast piston developed with Vertex know-how

Pro: Forged Piston developed in alternative to cast, with Vertex know how and race shape

Replica BB: Cast piston in original OE form for big bore cylinder

Pro Replica: Forged piston in original OE form

Pro BB:  Forged piston in original OE form for big bore cylinder

Pro Race: Forged piston developed with Vertex know-how and race shape profile

Pro HC: Forged piston developed with Vertex know-how, race shape profile and high compression ratio

Pro Race HC: Forged piston developed with Vertex know-how, one compression ring, race shape profile and high compression ratio