Originally Posted by
1200SportsterRider
And if the rears are shielded, oil still flows right through them, they, (the shields) could save the day if a bearing breaks up.
The grey Graupners are getting real scarce, the back side of the Xoars gets a groove worn around it and won't stay tight.
????
Bearings breaking up at less than 12K rpm? Not something I worry about unless I'm running 2 strokes at 17K plus rpm. They make high performance bearings with plastic retainers for that purpose. I have seen shields and seals pop off of bearings for no apparent reason so out they come.
I don't think anyone would disagree that the religious use of ARO is the best thing one can do to prevent an engine from rusting internally. If internal bearing shields or seals are left in place they impede the distribution of the ARO throughout the engine case at the end of the day's flying session. Eventually the factory bearing grease
will get washed out and replaced with corrosive combustion byproducts in shielded or sealed bearings. Better to have the ability to quickly and effectively flush out those corrosive elements with ARO than to have them trapped in the bearings.