Norrie Bodge wrote:Yes just pop one side off with a thin bladed flat screwdriver m8
& when fitting put that side on the drive sprocket side!
Deep groove ball bearings are obtainable in several configurations, with shield or seals on one side or both.
The commonly called “Z” metal
shields are ‘non-contact’ elements which, for the purposes of “2-Z” bearings retains the grease fitted to ensure long life.
Alternatively, the commonly called “R” rubber
seals are ‘contact’ elements which, for the purposes of “2-R” bearings retains the grease fitted to ensure long life
& to seal either side of them, up to an extent.
Obviously, either can be used in 2-Z or 2-R form without modification as they have their own built in lubrication.
If ever I have used the 2-R type & left one seal in place, I have always fitted the seal side toward the crankshaft to augment the crankshaft oil-seal, with the open side on the chain case side to receive necessary lubrication. I have never wanted to fit Z type & cannot imagine why anybody would, other than they nicked 'em from work, in which case I (oops!) I mean
they would pop off both shields.
However, once you start popping off only one shield or seal, you have to think about which way to fit them.
Fitting the other way around simply means that when the grease fitted to the deep groove ball bearings gets hot, it will migrate to anywhere it feels like in the void between it & the crankshaft oil-seal, risking premature wear.
It’s only hope of long term survival is if the crankshaft oil-seal fails, yet again…..
Posted: Sun Dec 09, 2018 11:12 am