The Namura Piston Kit NA-10000-3 is a 90.71 mm (+0.75 mm) replacement piston kit designed for select Honda TRX450 Foreman ATV engines. Manufactured by Namura and identified by manufacturer part number NA-10000-3 and vendor part number 187-100003, this kit provides a precision replacement solution for compatible overbore applications.
This piston kit fits 1998–2004 Honda TRX450FE Foreman ES models with SRA and 1998–2000 Honda TRX450FM Foreman S models with SRA. Confirm the engine configuration, existing bore, and required piston size before installation to ensure proper fitment. The +0.75 mm overbore specification is intended for engines machined to the corresponding cylinder size and should not be installed without verifying cylinder measurements and service requirements.
Important compatibility note: The Namura NA-10000-3 piston will not accept OEM piston rings, and the supplied rings are not compatible with an OEM piston. Use the correctly matched piston and ring set together during installation. Professional inspection and assembly are recommended to support proper clearance, compression, and engine performance.
Features:
- Size: 90.71 mm piston diameter with a +0.75 mm overbore specification
- Model: NA-10000-3 piston kit
- Brand: Namura
- Manufacturer part number: NA-10000-3
- Vendor part number: 187-100003
- Fitment: 1998–2004 Honda TRX450FE Foreman ES with SRA
- Fitment: 1998–2000 Honda TRX450FM Foreman S with SRA
- Compatibility: Will not accept OEM rings, and the included rings will not work with an OEM piston
- Application: Replacement piston kit for properly machined compatible Honda TRX450 Foreman engines
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]