PROX Top End Gasket Kit (base + head) for HUSQVARNA, KTM and GAS GAS 2003-2027

The PROX (embase + culasse) 36.6353 top end gasket kit is designed for KTM EXCF 350, SXF 350, XCF 350, HUSQVARNA FC 350, FE 350, FX 350 and GAS GAS ECF 350, EXF 350, MCF 350 from 2003 to 2027. As soon as the cylinder head or cylinder is removed, their gaskets must be replaced: crushed when tightened, they have taken the shape of the parts and will no longer seal. This kit groups under one part number the gaskets needed to reassemble the top end.

Specifications

• Brand: PROX
• Manufacturer part number: 36.6353
• 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 PROX?

ProX Racing Parts has been supplying engine and clutch parts to motocross riders since 1975, from its headquarters near Amsterdam. According to its catalogue, most of its parts are made in Japan, by manufacturers that also produce parts for the Japanese motorcycle makers.

Spare parts and items to plan

• Piston : see the selection
• Piston rings : PROX · WOSSNER
• Spark plug : see the selection
• 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?
The base gasket and the head gasket.

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:
GAS GAS ECF 350 2026
GAS GAS ECF 350 2025
GAS GAS ECF 350 2024
GAS GAS EXF 350 2025
GAS GAS EXF 350 2024
GAS GAS MCF 350 2025
GAS GAS MCF 350 2024
HUSQVARNA FC 350 2027
HUSQVARNA FC 350 2026
HUSQVARNA FC 350 2025
HUSQVARNA FC 350 2024
HUSQVARNA FC 350 2023
HUSQVARNA FE 350 2027
HUSQVARNA FE 350 2026
HUSQVARNA FE 350 2025
HUSQVARNA FE 350 2024
HUSQVARNA FX 350 2026
HUSQVARNA FX 350 2025
HUSQVARNA FX 350 2024
HUSQVARNA FX 350 2023
HUSQVARNA FX 350 2022
HUSQVARNA FX 350 2021
HUSQVARNA FX 350 2020
HUSQVARNA FX 350 2019
HUSQVARNA FX 350 2018
HUSQVARNA FX 350 2017
HUSQVARNA FX 350 2016
HUSQVARNA FX 350 2015
HUSQVARNA FX 350 2014
HUSQVARNA FX 350 2013
HUSQVARNA FX 350 2012
HUSQVARNA FX 350 2011
HUSQVARNA FX 350 2010
HUSQVARNA FX 350 2009
HUSQVARNA FX 350 2008
HUSQVARNA FX 350 2007
HUSQVARNA FX 350 2006
HUSQVARNA FX 350 2005
HUSQVARNA FX 350 2004
HUSQVARNA FX 350 2003
KTM EXCF 350 2027
KTM EXCF 350 2026
KTM EXCF 350 2025
KTM EXCF 350 2024
KTM SXF 350 2027
KTM SXF 350 2026
KTM SXF 350 2025
KTM SXF 350 2024
KTM SXF 350 2023
KTM XCF 350 2027
KTM XCF 350 2026
KTM XCF 350 2025
KTM XCF 350 2024
KTM XCF 350 2023