The NAMURA NA-10000-1K Top End Kit is designed for select Honda TRX450 Foreman ATVs and includes the components needed to service the engine’s top end. This kit includes a 90.21 mm piston, piston rings, wrist pin, retaining clips, top end bearing, and gasket kit. With an 11:1 compression ratio and a +0.25 mm oversize piston, the kit is intended for compatible applications requiring a precision replacement or cylinder bore service.
The piston uses NAMURA’s hypereutectic casting process, which increases silicon content to help control expansion, improve wear resistance, and withstand elevated cylinder temperatures. The piston skirts feature a rolled-on MOS2 coating made from Teflon and molybdenum. This coating is engineered to provide a strong bond, reduce friction, promote heat transfer, and help reduce the risk of cold seizures. Machined smooth heads help reflect combustion heat and limit carbon buildup, while anodized domes improve heat resistance and piston durability.
Fitment includes 1998–2004 Honda TRX450FE Foreman ES with SRA and 1998–2000 Honda TRX450FM Foreman S with SRA. Confirm the model year, trim, cylinder specification, and required oversize before installation. The manufacturer part number is NA-10000-1K, and the vendor part number is 186-10001.
Features:
- Kit contents: Includes piston, rings, wrist pin, retaining clips, top end bearing, and gasket kit.
- Piston size: 90.21 mm piston with a +0.25 mm oversize specification and 11:1 compression ratio.
- MOS2-coated skirts: Rolled-on Teflon and molybdenum coating helps reduce friction, improve heat transfer, and help prevent cold seizures.
- Machined smooth head: Helps reflect combustion heat and reduce carbon buildup on the piston crown.
- Anodized dome: Improves heat resistance and durability compared with a non-anodized piston dome.
- Hypereutectic construction: Higher silicon content helps control expansion, improve wear resistance, and withstand higher cylinder temperatures.
- Fitment: Compatible with select 1998–2004 Honda TRX450FE Foreman ES SRA models and 1998–2000 Honda TRX450FM Foreman S SRA models.
- Brand and part numbers: NAMURA manufacturer part number NA-10000-1K; vendor part number 186-10001.
Fitment:
1998 Honda TRX450FE Foreman ES [SRA]
1998 Honda TRX450FM Foreman S [SRA]
1999 Honda TRX450FE Foreman ES [SRA]
1999 Honda TRX450FM Foreman S [SRA]
2000 Honda TRX450FE Foreman ES [SRA]
2000 Honda TRX450FM Foreman S [SRA]
2001 Honda TRX450FE Foreman ES [SRA]
2001 Honda TRX450FM Foreman S [SRA]
2002 Honda TRX450FE Foreman ES [SRA]
2002 Honda TRX450FM Foreman S [SRA]
2003 Honda TRX450FE Foreman ES [SRA]
2003 Honda TRX450FM Foreman S [SRA]
2004 Honda TRX450FE Foreman ES [SRA]
2004 Honda TRX450FM Foreman S [SRA]