How to check the slingers without taking the crank out

[beemerguru]

Beautiful early R69S in the shop...20K original miles. Half of it's life in a museum.

I just used an engine bore scope on a later airhead to check some internals..clear picture and worked great.

The S owner is worried about slingers (normal with minimal paperwork) but working with the bore scope got me wondering if I can drop the left cylinder and use the bore scope to look at the slingers?

Has anyone tried this before, or do I pull the crank and go from there?

 

[20774]

Sorry, but I've never seen or heard of any way to check the slinger status without removing the crank from the engine. The way the slinger is snugged up to the bearings on the crank, I don't think even a piece of paper fits!

Here's a picture I took when I was starting to open up my R69S for slinger service. The arrows point to the slinger. It has to be very close because of the way the slinger works. The /2 has a low pressure oiling system. The slinger is a large "washer" but it has a cupped edge to it. Oil is directed into the flat part of the slinger and then the rotation from the engine slings the oil out to the cup region. The centrifugal force separates the solids from the oil, and the liquid finds it's way to passage in the crank web to the bearing surface. If the cup region gets way full, oil to the bearing is significantly reduced.

 

[69ZEFF65]

This is what an overstuffed and melted slinger looks like from the outside. Usually the front slinger will plug up before the rear one. Excessive wear on the left piston bin bushing is a sign the slinger is stuffed full of crap, the PO of this bike waited until the motor stopped. It's all better now.