OS 0.25 oversize piston ring kit for 450cc ATV engines found in Kodiak and Rhino models. This kit is designed to restore factory-like compression, tighten oil control, and seal the bore under demanding off‑road and farm work. It fits the YFM450FA (03-06), YFM450FG (07-14), YFM450FX (06-10), and YXR450F (06-09) configurations, delivering reliable power and crisp throttle response after high mileage or tough terrain. Replacing worn rings with this OS 0.25 kit helps reduce oil consumption and blow-by, helping you start easier and pull cleanly from low RPMs. Over time, wear on the top and secondary compression rings can allow compression leaks, while tired oil rings lose their wiping action on the bore. This aftermarket replacement provides an affordable, hard‑working solution that returns proper ring lands and sealing capability, giving you dependable performance on rough trails or busy farm days without breaking the bank.

Comprehensive Vehicle Fitment

Manufacturer	Models / Series	Years / Details
Aftermarket Replacement	YFM450FA Kodiak 450	2003-2006 OS 0.25 oversize kit
Aftermarket Replacement	YFM450FG Kodiak 450	2007-2014 OS 0.25 oversize kit
Aftermarket Replacement	YFM450FX Kodiak 450	2006-2010 OS 0.25 oversize kit
Aftermarket Replacement	YXR450F Rhino 450	2006-2009 OS 0.25 oversize kit

Product Specifications

Attribute	Details
OEM Reference Part Numbers	Not specified in listing
Type	Piston Ring Kit (OS 0.25 oversize)
Manufacturer	Aftermarket Replacement
Application	Yamaha 450cc ATV engines: YFM450FA 03-06; YFM450FG 07-14; YFM450FX 06-10; YXR450F 06-09
Oversize	OS +0.25 mm
Ring Configuration	Top compression ring, second compression ring, oil control ring (3-ring kit)
Contents	Top compression ring; Second compression ring; Oil control ring
Material	Not specified
Dimensions / Bore Size	Not specified

OEM & Aftermarket Cross-Reference Information

Part Number	Brand / Type	Cross-Reference Notes
190.04392	Aftermarket Replacement	OS oversize 0.25 kit; no explicit OEM cross-reference provided in listing; verify against Yamaha diagrams for your exact year/model

What's Included

The OS 0.25 piston ring kit for Yamaha 450 is designed to restore compression and proper oil control. The box typically includes the following components, aligned with standard Yamaha 450 OS ring kits:

• Top compression ring
• Second compression ring
• Oil control ring

Related parts such as pistons, wrist pins, and circlips are not included.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Precisely matched to Yamaha 450 OS oversize applications for Kodiak and Rhino engines, ensuring proper ring land engagement and seal geometry.
• OEM Cross-Reference Support: Designed to mirror OEM performance while offering a cost‑effective alternative; cross-reference compatibility may help with model-year variations.
• Premium Materials & Precision Machining: Oversize rings engineered to restore compression and seal integrity while minimizing friction and wear.
• Performance Restoration: Reclaims throttle response, smoother starts, and consistent power delivery after many miles of rough terrain.
• Oil Control & Blow-By Reduction: Reestablishes proper wiping action to curb oil consumption and reduce blow-by under load.
• Value for Trail & Farm Use: A practical, affordable aftermarket option built for reliability in demanding outdoor conditions.

Installation Notes:

• Verify bore compatibility: Ensure bore size matches OS 0.25 oversize specification before installation.
• Ring orientation & spacing: Install each ring in its proper orientation and stagger end gaps to minimize blow-by.
• Cleanliness is critical: Thoroughly clean all ring lands and grooves; remove carbon buildup to avoid binding rings.
• Use assembly lubricant: Apply light engine oil to rings and piston skirts to prevent dry friction during initial startup.
• Ring expander and careful handling: Use a proper ring expander to avoid nicking or deforming rings during installation.
• Ring gaps & seating: Position gaps away from each other (e.g., 120 degrees apart) and verify final seating before reassembly.

Why Upgrade?

Running a worn piston ring set leads to reduced compression, increased oil consumption, and rough, unreliable starts. This OS 0.25 kit restores sealing and oil control, delivering dependable power and smoother operation when you’re pushing a Kodiak or Rhino through rough trails or long farm days. Replacing the worn rings with this kit helps bring the engine back to reliable, factory-like performance.