ATHENA Cylinder Base Gasket for YAMAHA TT 250, XT 250 1980-1984

ATHENA offers this cylinder base gasket for YAMAHA TT 250, XT 250 1980-1984. The base gasket sits under the cylinder, on the crankcase. Crushed when tightened, it cannot be reused: replace it every time the cylinder comes off.

Why does the thickness matter?

The benefits:

• The OE thickness keeps the cylinder height intended by the manufacturer.
• Another thickness lets you correct piston-to-head clearance after machining or adjust the port timing of a 2-stroke.
• A new gasket keeps the bottom end sealed against oil and gases.

Why choose ATHENA?

Athena, founded in 1973 by Giovanni Mancassola near Vicenza and based in Alonte (Italy), designs gaskets, pistons and cylinder kits; it supplies original equipment to manufacturers such as KTM, Ducati, Fantic and Triumph.

When should you replace the base gasket on your YAMAHA TT 250?

Every time the cylinder comes off: piston change, top-end rebuild or cylinder inspection. Oil or mixture seeping at the base of the cylinder also points to a tired gasket.

No manufacturer figure in hours for this model. Cross-Mania guideline: compression check every 20 h of hard use and every 40 h of leisure riding.

Specifications and fitting tips

• Thickness : OE
• Manufacturer part number: S410485006025

Cross-Mania tip: Choose the OE thickness if the cylinder and head have not been machined; if in doubt, measure the squish with solder wire before final assembly.

Spare parts and items to plan

• Top-end gasket kit : ATHENA P400485600252 · ATHENA P400485600268
• Piston : see the selection
• Piston rings : see the selection
• Coolant : LIQUI MOLY 1 L · TWIN AIR

Compatibility

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

Fits:
YAMAHA TT 250 1984
YAMAHA TT 250 1983
YAMAHA TT 250 1982
YAMAHA TT 250 1981
YAMAHA TT 250 1980
YAMAHA XT 250 1984
YAMAHA XT 250 1983
YAMAHA XT 250 1982
YAMAHA XT 250 1981
YAMAHA XT 250 1980