Restore the upper-end performance of your ATV with the Namura NA-10043-3K Top End Kit. This 87.23 mm, 11:1 compression kit is designed for select Honda TRX420 Rancher models and includes the essential components needed for a dependable top-end rebuild. The kit includes a piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit for convenient installation and complete coverage during service.
The Namura piston uses a hypereutectic casting process that increases silicon content to help reduce expansion and improve wear resistance under elevated cylinder temperatures. Its MOS2, or Teflon/molybdenum, coated skirts use a rolled-on application process designed to create a stronger bond than conventional spray-on coatings. This coating helps reduce friction, improve heat transfer, and minimize the risk of cold seizures during operation.
The machined smooth piston head helps reflect combustion heat and reduce carbon buildup, supporting piston protection and consistent engine performance. An anodized dome improves heat resistance and durability, while the 11:1 compression ratio is suited to applications requiring a performance-oriented replacement piston. The included gasket kit, bearing, rings, wrist pin, and clips help simplify the rebuild process.
Fitment includes 2014–2016 Honda TRX420FA1 Rancher 4x4 AT DCT with SRA; 2014–2017 Honda TRX420FA2 Rancher 4x4 AT DCT EPS with SRA; and 2014–2016 Honda TRX420FE1 Rancher 4x4 ES with SRA. Verify the exact model designation, year, bore specification, and engine configuration before installation. Manufacturer and vendor part number: NA-10043-3K.
Features:
- Complete top-end kit includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- 87.23 mm piston size with an 11:1 compression ratio
- MOS2 Teflon/molybdenum coated skirts help reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined smooth head helps reflect combustion heat and reduce carbon buildup
- Anodized dome improves heat resistance and piston durability
- Hypereutectic casting process provides reduced expansion and improved wear resistance
- Fits select 2014–2017 Honda TRX420 Rancher 4x4 models with SRA
- Brand: Namura; manufacturer and vendor part number: NA-10043-3K
Fitment:
2009 Honda TRX420FA Rancher AT [IRS]
2009 Honda TRX420FE Rancher ES [SRA]
2009 Honda TRX420FM Rancher [SRA]
2009 Honda TRX420FPA Rancher w/PS [IRS]
2009 Honda TRX420FPE Rancher ES w/PS [SRA]
2009 Honda TRX420FPM Rancher w/PS [SRA]
2009 Honda TRX420TE Rancher 2x4 ES [SRA]
2009 Honda TRX420TM Rancher [SRA]
2010 Honda TRX420FA Rancher AT [IRS]
2010 Honda TRX420FE Rancher ES [SRA]
2010 Honda TRX420FM Rancher [SRA]
2010 Honda TRX420FPA Rancher w/PS [IRS]
2010 Honda TRX420FPE Rancher ES w/PS [SRA]
2010 Honda TRX420FPM Rancher w/PS [SRA]
2010 Honda TRX420TE Rancher 2x4 ES [SRA]
2010 Honda TRX420TM Rancher [SRA]
2011 Honda TRX420FA Rancher AT [IRS]
2011 Honda TRX420FE Rancher ES [SRA]
2011 Honda TRX420FM Rancher [SRA]
2011 Honda TRX420FPA Rancher w/PS [IRS]
2011 Honda TRX420FPE Rancher ES w/PS [SRA]
2011 Honda TRX420FPM Rancher w/PS [SRA]
2011 Honda TRX420TE Rancher 2x4 ES [SRA]
2011 Honda TRX420TM Rancher [SRA]
2012 Honda TRX420FA Rancher AT [IRS]
2012 Honda TRX420FE Rancher ES [SRA]
2012 Honda TRX420FM Rancher [SRA]
2012 Honda TRX420FPA Rancher w/PS [IRS]
2012 Honda TRX420FPE Rancher ES w/PS [SRA]
2012 Honda TRX420FPM Rancher w/PS [SRA]
2012 Honda TRX420TE Rancher 2x4 ES [SRA]
2012 Honda TRX420TM Rancher [SRA]
2013 Honda TRX420FA Rancher AT [IRS]
2013 Honda TRX420FE Rancher ES [SRA]
2013 Honda TRX420FM Rancher [SRA]
2013 Honda TRX420FPA Rancher w/PS [IRS]
2013 Honda TRX420FPE Rancher ES w/PS [SRA]
2013 Honda TRX420FPM Rancher w/PS [SRA]
2013 Honda TRX420TE Rancher 2x4 ES [SRA]
2013 Honda TRX420TM Rancher [SRA]
2014 Honda TRX420FA Rancher AT [IRS]
2014 Honda TRX420FA1 Rancher 4x4 AT DCT [SRA]
2014 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2014 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2014 Honda TRX420FM1 Rancher 4x4 [SRA]
2014 Honda TRX420FM2 Rancher 4x4 EPS [SRA]
2014 Honda TRX420FPA Rancher w/PS [IRS]
2014 Honda TRX420TE1 Rancher 2x4 ES [SRA]
2014 Honda TRX420TM1 Rancher [SRA]
2015 Honda TRX420FA1 Rancher 4x4 AT DCT [SRA]
2015 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2015 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2015 Honda TRX420FM1 Rancher 4x4 [SRA]
2015 Honda TRX420FM2 Rancher 4x4 EPS [SRA]
2015 Honda TRX420TE1 Rancher 2x4 ES [SRA]
2015 Honda TRX420TM1 Rancher [SRA]
2016 Honda TRX420FA1 Rancher 4x4 AT DCT [SRA]
2016 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2016 Honda TRX420FA5 Rancher 4x4 AT DCT [IRS]
2016 Honda TRX420FA6 Rancher 4x4 AT DCT EPS [IRS]
2016 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2016 Honda TRX420FM1 Rancher 4x4 [SRA]
2016 Honda TRX420FM2 Rancher 4x4 EPS [SRA]
2016 Honda TRX420TE1 Rancher 2x4 ES [SRA]
2016 Honda TRX420TM1 Rancher [SRA]
2017 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2017 Honda TRX420FA5 Rancher 4x4 AT DCT [IRS]
2017 Honda TRX420FA6 Rancher 4x4 AT DCT EPS [IRS]
2017 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2017 Honda TRX420FM1 Rancher 4x4 [SRA]
2017 Honda TRX420TM1 Rancher [SRA]
2018 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2018 Honda TRX420FA5 Rancher 4x4 AT DCT [IRS]
2018 Honda TRX420FA6 Rancher 4x4 AT DCT EPS [IRS]
2018 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2018 Honda TRX420FM1 Rancher 4x4 [SRA]
2018 Honda TRX420TM1 Rancher [SRA]
2023 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2023 Honda TRX420FA5 Rancher 4x4 AT DCT [IRS]
2023 Honda TRX420FA6 Rancher 4x4 AT DCT EPS [IRS]
2023 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2023 Honda TRX420FM1 Rancher 4x4 [SRA]
2023 Honda TRX420FM2 Rancher 4x4 EPS [SRA]
2023 Honda TRX420TE1 Rancher 2x4 ES [SRA]
2023 Honda TRX420TM1 Rancher [SRA]
2024 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA]
2024 Honda TRX420FA5 Rancher 4x4 AT DCT [IRS]
2024 Honda TRX420FA6 Rancher 4x4 AT DCT EPS [IRS]
2024 Honda TRX420FE1 Rancher 4x4 ES [SRA]
2024 Honda TRX420FM1 Rancher 4x4 [SRA]
2024 Honda TRX420FM2 Rancher 4x4 EPS [SRA]
2024 Honda TRX420TE1 Rancher 2x4 ES [SRA]
2024 Honda TRX420TM1 Rancher [SRA]