ATHENA Top End Gasket Kit for ATHENA Big Bore cylinder kit Ø85 mm for YAMAHA WRF 250, YZF 250 and FANTIC XEF 310 2019-2025

The ATHENA P400485160073 top end gasket kit is designed for YAMAHA WRF 250, YZF 250 and FANTIC XEF 310 from 2019 to 2025. The top end gasket kit brings together the gaskets to replace every time the cylinder head or cylinder comes off. A gasket crushed by tightening never gets its shape back: refitting it means risking a compression, coolant or oil leak, and having to strip everything down again.

Key features

• Head, base and exhaust gaskets, O-rings and washers, depending on the model.
• Laser cutting and surface treatments for consistent sealing.
• Designed by Athena, an OEM supplier, and validated on test benches.

Specifications

• Brand: ATHENA
• Manufacturer part number: P400485160073
• EAN code: 8053300713776
• For ATHENA cylinder kit ref. P400120100001 (Ø85 mm), P400485100073 (Ø85 mm), P400485100105 (Ø85 mm), P400485100106 (Ø85 mm)
• Weight: 70 g
• Engine: 4-stroke

When to replace it?

• Coolant or oil seeping at the head/cylinder or cylinder/crankcase joint.
• Coolant level dropping, bubbles in the radiator.
• Hissing or black marks where the exhaust leaves the cylinder.

At every piston change and every time the cylinder head or cylinder is removed, even for a simple inspection. Gaskets cost little compared with the work of stripping the engine.

Fitting tips

1. Clean the gasket faces without scratching them (plastic scraper, solvent): they must be clean, dry and free of burrs.
2. Fit the gaskets dry, without sealant, unless the workshop manual says otherwise.
3. Refit a base gasket of the same thickness as the old one, unless you are deliberately adjusting the squish.
4. Tighten the cylinder head in a criss-cross pattern, in several stages, up to the manufacturer's torque.
5. While it's apart, replace the spark plug and refill the coolant.
6. After break-in, check the torque with the engine cold and make sure there are no leaks.

Why ATHENA?

Athena, an Italian company founded in 1973 near Vicenza, designs gaskets, pistons and cylinder kits for motorcycles. An OEM supplier to KTM, Ducati, Fantic, Piaggio and Triumph and a partner of the MXGP world championship, it develops its parts on the test bench and on the track with racing teams.

Spare parts and items to plan

• ATHENA cylinder kit : ATHENA P400485100073 · ATHENA P400120100001 · ATHENA P400485100105
• Piston : ATHENA S5F08500005 · ATHENA S5F08500007
• Piston rings : ATHENA
• Spark plug : NGK 96067 · NGK 4218
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L

Frequently asked questions

What does the kit contain?
Depending on the model: head gasket, base gasket, exhaust gasket, O-rings and washers. Compare with your original gaskets if you're unsure.

Should I replace it along with the piston?
Yes: as soon as the cylinder head and cylinder are off, new gaskets go back on. It's the right time to fit a new piston kit and new rings if the engine has some hours on it.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
FANTIC XEF 310 2025
FANTIC XEF 310 2024
FANTIC XEF 310 2023
YAMAHA WRF 250 2023
YAMAHA WRF 250 2022
YAMAHA WRF 250 2021
YAMAHA WRF 250 2020
YAMAHA YZF 250 2024
YAMAHA YZF 250 2023
YAMAHA YZF 250 2022
YAMAHA YZF 250 2021
YAMAHA YZF 250 2020
YAMAHA YZF 250 2019