Hi gang, total novice here not afraid to reveal my ignorance to strangers. I have the dirty pig stripped up to the clutch pushrod on my way to investigate a potential rear main seal oil leak and various other tranny/clutch/spline shtuff. Having fun! 

So I've removed the clutch pushrod assembly and am looking at what looks to be an o-ring with a very small compression spring around it. The o-ring is stuffed (probably contributing to another leak which initially thought was the clutch boot) and for the life of me cannot figure out a) the o-ring part b) how to replace it c) a better understanding of how this assembly works. Any suggestions are welcome!

I planned to proceed with the rear main oil seal mission in the next few day. Thanks in advance to the folks helping me get this far!!

It is an oil seal and prevents the oil from inside the gearbox going down the centre of the main input shaft to the clutch.
I have never found a source except for factory and it is more often than not quite OK. If you look at it from the rear of the gearbox you are looking at the inside of the seal, the oil side. Many have installed them the other way and found a leak when all assembled. The inside of the boot is lubed by the gearbox oil and is usually the source of oil leaks in that area. If the clutch adjustment screw is too far through the lip on the actuating lever wont seal due to too much angle.
If the seal is leaking then the oil will appear at the drain hole in the bottom of the intermmediate housing. To get it out just a strong wire hook will pull it out or you may be able to get a bar down the shaft after you get the gearbox out but that is unlikely.

Thanks Rick, I got a better picture. Not sure I describe the location of the oil seal correctly. This pic is rotated 90 degrees counter clockwise... that's the clutch lever in the pic. I have not pulled the transmission yet. Which RealOEM diagram shows this seal? The bugger isn't described in Clymers TMK either. Still hopeful I didn't destroy my bike...

kstar wrote: Which RealOEM diagram shows this seal?

#12  part# 23 21 1 451 159.

Thanks Inge, Rick. I feel much better about life now. 

I'm going to follow this lead from here: https://www.k100-forum.com/t620-clutch-pushrod-oil-seal

Wish me luck. Over and out.

kstar wrote:Thanks Inge, Rick. I feel much better about life now. 

I'm going to follow this lead from here: https://www.k100-forum.com/t620-clutch-pushrod-oil-seal

Wish me luck. Over and out.

For any other newbs I found this clutch description helpful to understand input/output shaft.

http://www.motobrick.com/index.php?topic=332.0