PROX crankshaft bearing and seal kit for BETA RR 250, RR 300, RX 300, XTRAINER 250 LC, XTRAINER 300 LC from 2013 to 2023

PROX offers this crankshaft bearing and seal kit for BETA RR 250, RR 300, RX 300, XTRAINER 250 LC, XTRAINER 300 LC from 2013 to 2023. The crankshaft spins on two large bearings in the cases, protected by oil seals. They take all the engine’s force; after many hours they develop play and vibration appears.

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 PROX?

ProX uses Koyo or NTN bearings, largely made in Japan in OEM factories, with the original internal clearance (C3 / C4).

When should you replace the bearings on your BETA RR 300?

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

Recommended hours for a bottom-end rebuild (manufacturer recommendation for the Beta RR 250 / 300 two-stroke):

• Normal use: every 90 h.
• Racing: no Beta figure; have the wear checked at every top-end rebuild.

Specifications and fitting tips

• Application: Crankshaft
• Built to exact OEM specifications for maximum performance and durability
• Include all bearings/seals required to replace the component

Cross-Mania tip: Heat the cases to remove and fit the bearings without forcing them, and replace the oil seals at the same time.

Compatibility

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

Fits:
BETA RR 250 2021
BETA RR 250 2020
BETA RR 250 2019
BETA RR 250 2018
BETA RR 250 2017
BETA RR 250 2016
BETA RR 250 2015
BETA RR 250 2014
BETA RR 250 2013
BETA RR 300 2023
BETA RR 300 2022
BETA RR 300 2021
BETA RR 300 2020
BETA RR 300 2019
BETA RR 300 2018
BETA RR 300 2017
BETA RR 300 2016
BETA RR 300 2015
BETA RR 300 2014
BETA RR 300 2013
BETA RX 300 2021
BETA XTRAINER 250 LC 2020
BETA XTRAINER 250 LC 2019
BETA XTRAINER 300 LC 2023
BETA XTRAINER 300 LC 2022
BETA XTRAINER 300 LC 2021
BETA XTRAINER 300 LC 2020
BETA XTRAINER 300 LC 2019
BETA XTRAINER 300 LC 2018
BETA XTRAINER 300 LC 2017
BETA XTRAINER 300 LC 2016
BETA XTRAINER 300 LC 2015