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Namura Piston Assembly - 100mm Bore - NA-40004

  • Part #: 133191S
  • Manufacturer Part #: NA-40004

MSRP Price: $107.78

Our Price: $97.00

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$10.78 (10%)
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Overview of Namura Piston Assembly - 100mm Bore - NA-40004

  • High-performance Namura pistons are engineered in the USA, manufactured in Taiwan
  • High-silicon content Hypereutectic cast aluminum material for less heat expansion, tighter clearances, increased hardness, longer life and reduced scuffing
  • Features machined, smooth piston crowns for reduced carbon buildup, increased horsepower and fuel economy
  • Hard anodized crowns are 75% stronger than non-anodized, providing minimal expansion and reducing the chance of cold seizures when combined with Teflon/Molybdenum coated skirts
  • MOS2 (Teflon/Molybdenum) coated skirts perform at the highest standards, reducing friction and heat for added power and longevity
  • Namura rings match the OEM design except as noted
  • -B (.0004 in.) and -C (.0008 in.) fractional oversize pistons, available for some applications, extend the life of your expensive cylinder by renewing the original clearance if it's slightly worn, avoiding an expensive sleeve installation
  • Piston assemblies include ring(s), wrist pin and circlips


  • Included Items:
    (1) Pison
    (1) Ring set
    (2) Wrist pin clips
    (1) Wrist pin

Specs for Namura Piston Assembly - 100mm Bore - NA-40004

Bore Size 100 mm
Type Piston Assembly
Type - Pistons & Piston Rings Piston w/Ring Set
Units Each
Weight 1.40 lbs

Specs for Namura Piston Assembly - 100mm Bore - NA-40004

Bore Size 100 mm
Type Piston Assembly
Type - Pistons & Piston Rings Piston w/Ring Set
Units Each
Weight 1.40 lbs

Fitment for Namura Piston Assembly - 100mm Bore - NA-40004

See if this part fits your ride

Part 133191S fits the following machines

Yamaha
  • 2004 Yamaha YFM660F Grizzly 4x4
  • 2003 Yamaha YFM660F Grizzly 4x4
  • 2002 Yamaha YFM660F Grizzly 4x4
  • 2008 Yamaha YFM660FA Grizzly 4x4
  • 2007 Yamaha YFM660FA Grizzly 4x4
  • 2006 Yamaha YFM660FA Grizzly 4x4
  • 2005 Yamaha YFM660FA Grizzly 4x4
  • 2006 Yamaha YFM660FAH Grizzly 4x4 Hardwoods Hunter Edition
  • 2005 Yamaha YFM660FAH Grizzly 4x4 Hardwoods Hunter Edition
  • 2006 Yamaha YFM660FAHD Grizzly 4x4 Ducks Unlimited Edition
  • 2005 Yamaha YFM660FAHW Grizzly 4x4 Wetlands Hunter Edition
  • 2006 Yamaha YFM660FASE Grizzly 4x4 Special Edition
  • 2005 Yamaha YFM660FASE Grizzly 4x4 Special Edition
  • 2008 Yamaha YFM660FG Grizzly 4x4
  • 2007 Yamaha YFM660FG Grizzly 4x4
  • 2008 Yamaha YFM660FGH Grizzly 4x4 Hunter Edition
  • 2007 Yamaha YFM660FGH Grizzly 4x4 Hunter Edition
  • 2003 Yamaha YFM660F-GY Grizzly 4x4 Limited Edition
  • 2004 Yamaha YFM660FH Grizzly 4x4 Hardwoods Hunter Edition
  • 2002 Yamaha YFM660FH Grizzly 4x4 Hunter Edition
  • 2003 Yamaha YFM660FH-H Grizzly 4x4 Hardwoods Hunter Edition
  • 2004 Yamaha YFM660FH-WL Grizzly 4x4 Wetlands Hunter Edition
  • 2003 Yamaha YFM660FH-WL Grizzly 4x4 Wetlands Hunter Edition
  • 2005 Yamaha YFM660FLE Grizzly 4x4 Limited Edition
  • 2004 Yamaha YFM660FLE Grizzly 4x4 Limited Edition
  • 2005 Yamaha YFM660R Raptor
  • 2004 Yamaha YFM660R Raptor
  • 2003 Yamaha YFM660R Raptor
  • 2002 Yamaha YFM660R Raptor
  • 2001 Yamaha YFM660R Raptor
  • 2005 Yamaha YFM660RLE Raptor Limited Edition
  • 2004 Yamaha YFM660RLE Raptor Limited Edition
  • 2003 Yamaha YFM660RLE Raptor Limited Edition
  • 2002 Yamaha YFM660RLE Raptor Limited Edition
  • 2007 Yamaha YXR660F Rhino 4x4
  • 2007 Yamaha YXR660FA Rhino 4x4
  • 2006 Yamaha YXR660FA Rhino 4x4
  • 2005 Yamaha YXR660FA Rhino 4x4
  • 2004 Yamaha YXR660FA Rhino 4x4
  • 2006 Yamaha YXR660FAEX Rhino 4x4 Exploring Edition
  • 2006 Yamaha YXR660FAH Rhino 4x4 Hunter Edition
  • 2005 Yamaha YXR660FAH Rhino 4x4 Hunter Edition
  • 2004 Yamaha YXR660FAH Rhino 4x4 Hunter Edition
  • 2006 Yamaha YXR660FAH Rhino 4x4 Hunter Exploring Edition
  • 2007 Yamaha YXR660FASE Rhino 4x4 Special Edition
  • 2006 Yamaha YXR660FASE Rhino 4x4 Special Edition
  • 2007 Yamaha YXR660FDU Rhino 4x4 Ducks Unlimited Edition
  • 2007 Yamaha YXR660FEX Rhino 4x4 Exploring Edition
  • 2007 Yamaha YXR660FH Rhino 4x4 Hunter Edition
  • 2007 Yamaha YXR660FSE Rhino 4x4 Special Edition
  • 2007 Yamaha YXR660FSP Rhino 4x4 Sport Edition
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Instructions and Manuals for Namura Piston Assembly - 100mm Bore - NA-40004