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90mm Standard Size Piston for 420cc Clone Engines
420cc 90mm Big Block Clone Piston
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90mm Standard Size Piston for 420cc Clone Engines

Part Number: 190F-12001-A
Online Price: $24.99
Stock 90mm Cast Piston – Standard Bore for 420cc Big Block Clone Engines
Availability: In Stock.

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Description

Stock 90mm Cast Piston – Standard Size for 420cc Big Block Clone Engines


This 90mm Standard-Size Cast Piston is designed for most 420cc Honda GX390 Big Block Clone Engines, commonly used in racing go-karts, minibikes, and performance small engines. With a dish-top crown and precise machining, this piston delivers reliable compression and durability for both stock and modified applications.


Due to manufacturing tolerances across various clone engine brands, always verify bore size, compression height, and wrist pin specs before ordering to ensure proper fitment.


Piston Specifications:

  • Material: Cast aluminum
  • Crown Type: Dish top (~.040" depth)
  • Skirt Length: 2.613" / 66.4mm
  • Compression (Pin) Height: 1.498" / 38mm
  • Wrist Pin Journal: 0.788" / 20mm
  • Piston Diameter: 3.542" / 90mm
  • Top Ring Land: 0.080"
  • Second Ring Land: 0.080"
  • Oil Ring Land: 0.110"


Important Notes:

  • This listing is for the piston only.
  • Rings, wrist pin, and circlips are sold separately.
  • Always check your engine specs prior to installation.


This 90mm cast piston is a dependable choice for builders seeking a standard-size replacement or a solid foundation for a performance upgrade. Ideal for clone engines used in racing or high-demand applications.

FAQ

Q1: Will this piston fit all 420cc clone engines?
A: While 90mm is the standard bore for most 420cc GX390-style clone engines, dimensions can vary slightly between manufacturers. We strongly recommend measuring your bore and confirming piston specs before purchase.


Q2: Is this piston sold with rings and wrist pin?
A: No, this listing is for the piston only. Rings, wrist pin, and clips are sold separately.


Q3: What kind of crown does the piston have?
A: It features a dish-top crown with an approximate depth of 0.040”, suitable for stock or mild performance builds.


Q4: What is the wrist pin size?
A: The wrist pin journal is 0.788” (20mm), matching most 420cc big block clone engine configurations.


Q5: Can this piston be used in racing go-karts or minibikes?
A: Yes, this piston is often used in performance small engines like go-karts and minibikes built with 420cc GX390-style clone engines.

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