ATHENA Crankshaft Bearing and Seal Kit for BETA RX 250, RX 350, XTRAINER 250, XTRAINER 300 2026

ATHENA offers this engine bearing and seal kit for BETA RX 250, RX 350, XTRAINER 250, XTRAINER 300 2026. The crankshaft and gearbox shafts spin on bearings in the cases; oil seals keep the oil in around the shafts.

What is this bearing made of?

Races and balls (or rollers) in hardened chrome steel, 100Cr6 type: a very hard steel that withstands the fatigue of millions of engine revolutions.

• Open bearing: unsealed, it is lubricated and cooled by the engine oil; clean oil is its best protection.
• C3 / C4 internal clearance: slightly more clearance than normal for a hot engine’s expansion; always refit the original clearance.
• Limit: it dislikes dust and old oil; running short of oil destroys it within minutes.

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 bearings on your BETA RX 250?

Unusual vibration, a deep knock that follows engine speed or play in the con-rod: the bottom end needs a rebuild.

The manufacturer publishes no hour interval for this model: have the con-rod play checked at every piston change. Cross-Mania guideline: rebuild the bottom end every 2 to 3 top-end rebuilds.

Specifications and fitting tips

• Manufacturer part number: P400060444004

Spare parts and items to plan

• Complete engine gasket kit : ATHENA · PROX
• Connecting rod kit : PROX 03.7319 · PROX 03.7314
• Gearbox oil : LIQUI MOLY 10W30 1 L · LIQUI MOLY 1 L

Compatibility

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

Fits:
BETA RX 250 2026
BETA RX 350 2026
BETA XTRAINER 250 2026
BETA XTRAINER 300 2026