Sealed bearing on crankcase side?

[Davidsquaredson]

This picture was posted on another forum. Someone put the bearing in with both sides sealed. BeAring is pregreased. As advertised this grease is supposed to last for the design life of the bearing. So why do we remove them? Is this not an improvement over original and relying on case oil getting into the gear sufficiently and without any debris?

[Shipleystevep]

I’m interested in this too, realise it a bit different but my replacement end plate bearing was sealed both sides. I was advised to remove the seals but didn’t really understand why?

[tony172]

Also interested, can't see any reason why you'd need to remove them

[EddieStone]

It's a critical part to rely on a greased bearing, especially as it gets quite hot. That's my opinion based on guesswork and little else

[Warkton Tornado No.1]

There are three main types of variations on the generic deep groove ball bearing:

Open
Shielded
Sealed

The 2RS type has lubrication built in.

That's not where it ends, though.

Maximum speeds are less for grease lubrication than for oil. That's because of the difference in lubricity. Greased, sealed bearings can & do get hot. The oil, however, is constantly moving around in it's much larger confines, shedding heat as it goes via the internal ribbing of the crankcase assembly.

Personally, I think the crankcase lubrication via an oil shower/mist is a very good method, so I remain true to the original design intent.

Where I do vary is by using ATF, which cured a slipping six plate clutch, so I've been using it for years in my own & other Lambrettas.

[Tractorman]

You should pick the seal out on the gearbox side to allow oil lubrication. You will notice that the manufacturer of the bearing is not very generous with the grease!

[Grumpy225]

If you’re having that level of seal problems then you need to address how you’re building your motor.

The seal on that bearing doesn’t have a spring in it like a normal seal. It’s essentially a drag inducing dust cover and a waste of time to run it.

[dirtyhandslopez]

You say the "bearing is pregreased"
How do you know the manufacturer actually put grease in the bearing in your engine without removing the seal/cover?
Manufacturers are not perfect and make mistakes all the time.
I have opened sealed bearings only to find no grease had be applied to the bearing before sealing them.
Is it worth the risk to run the bearing without checking?

[Davidsquaredson]

Great answers. Thanks!

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