Restore upper-engine performance with the NAMURA NA-10043-4K Top End Kit, designed for select Honda Rancher 4x4 ATV models. This 87.48 mm, +1.00 mm oversize kit features an 11:1 compression ratio and includes the essential components needed for a reliable top-end rebuild: piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit. The kit is manufactured for accurate fitment and dependable service in compatible Honda engines.
The NAMURA piston uses a MOS2, or Teflon/Molybdenum, coated skirt applied through a rolled-on process for a strong, durable bond. This coating helps improve heat transfer, reduce friction, and minimize the risk of cold seizures. The machined smooth head is designed to reflect combustion heat and help reduce carbon buildup, supporting piston protection and consistent engine operation. An anodized dome improves heat resistance and durability, while the hypereutectic casting process adds silicon for controlled expansion, increased wear resistance, and improved performance under higher cylinder temperatures.
Fitment includes 2014-2016 Honda TRX420FA1 Rancher 4x4 AT DCT [SRA], 2014-2017 Honda TRX420FA2 Rancher 4x4 AT DCT EPS [SRA], and 2014-2016 Honda TRX420FE1 Rancher 4x4 ES [SRA]. Verify the model designation, year, bore requirement, and compression specifications before installation. The manufacturer part number and vendor part number are both NAMURA NA-10043-4K.
Features:
- Complete Top End Kit: Includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- 87.48 mm Bore: +1.00 mm oversize piston specification for compatible Honda Rancher applications
- 11:1 Compression Ratio: Supports the specified engine rebuild configuration
- MOS2-Coated Skirt: Rolled-on Teflon/Molybdenum coating helps reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined Smooth Head: Helps reflect combustion heat and reduce carbon buildup on the piston crown
- Anodized Dome: Provides increased heat resistance and durability compared with non-anodized piston domes
- Hypereutectic Casting: Higher silicon content helps control expansion and improve wear resistance at elevated cylinder temperatures
- Fitment: For select 2014-2017 Honda TRX420FA1, TRX420FA2, and TRX420FE1 Rancher 4x4 models
- Brand and Part Number: NAMURA manufacturer and vendor part number NA-10043-4K
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]