PROX Crankshaft Oil Seal for KTM SX 50, HUSQVARNA TC 50 and GAS GAS MC 50 2013-2026

The PROX 41.6-263561 crankshaft oil seal is designed for KTM SX 50, HUSQVARNA TC 50 and GAS GAS MC 50 from 2013 to 2026. On a two-stroke, the bottom end works as a pump: it has to be perfectly sealed. That's the crankshaft oil seal's job; once worn, it lets air in and the engine becomes temperamental.

Specifications

• Brand: PROX
• Manufacturer part number: 41.6-263561
• Dimensions: 26x35x6 mm
• Engine: 2-stroke

When to replace it?

• Unstable idle, revs hanging or rising on their own.
• Gearbox oil level dropping, white smoke (clutch-side seal).
• Oil or black marks on the ignition side.

At every bottom end rebuild, and as soon as these symptoms appear.

Fitting tips

1. Drive out the old seal without scratching the housing or the crankshaft.
2. Grease the lip and press the seal in perfectly square, lip facing the inside of the engine.
3. Protect the lip as you slide it over the crankshaft thread or key.
4. Refit the cover with a new gasket.

Why PROX?

Founded in 1975 and based near Amsterdam, ProX specialises in engine and clutch wear parts for off-road bikes. The brand has most of its range made in Japan, by OEM suppliers, for quality on a par with the original parts.

Spare parts and items to plan

• Crankshaft bearings and seals : see the selection
• Ignition cover gasket : ATHENA
• Complete engine gasket kit : MOOSE 822347MSE · MOOSE 811337MSE

Frequently asked questions

Do the crankcases have to be split?
Not always: on some engines, the ignition-side seal can be replaced without splitting the cases. During a rebuild, replace it along with the crankshaft bearing and seal kit.

Compatibility

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

Fits:
GAS GAS MC 50 2026
GAS GAS MC 50 2025
GAS GAS MC 50 2024
GAS GAS MC 50 2023
GAS GAS MC 50 2022
GAS GAS MC 50 2021
HUSQVARNA TC 50 2026
HUSQVARNA TC 50 2025
HUSQVARNA TC 50 2024
HUSQVARNA TC 50 2023
HUSQVARNA TC 50 2022
HUSQVARNA TC 50 2021
HUSQVARNA TC 50 2020
HUSQVARNA TC 50 2019
HUSQVARNA TC 50 2018
HUSQVARNA TC 50 2017
KTM SX 50 2026
KTM SX 50 2025
KTM SX 50 2024
KTM SX 50 2023
KTM SX 50 2022
KTM SX 50 2021
KTM SX 50 2020
KTM SX 50 2019
KTM SX 50 2018
KTM SX 50 2017
KTM SX 50 2016
KTM SX 50 2015
KTM SX 50 2014
KTM SX 50 2013