Z400 oil leak/seal question

[Nebr_Rex]

The clutch pushrod is 7mm, the same size as the valve. The diameter of
the pushrod seal bore is 36mm and steps up to 37.5mm then down to 33mm
to where the seal sits.

.edit: the seal sits .600 in. in from the outside edge

.

 

[Powderfinger]

The way that pushrod seal is made (on mine anyhow) there are two sealing lips on it and there is a space in between kind of like a groove. I found an o ring that fit in that groove just right (not to tight but not to loose). then I pushed the pushrod through making sure it wasn't unseating the o ring. The o ring fits reasonably tight around the pushrod and at the same time it is pushed outward against the seal. It stopped the leak just fine so far.

I don't know what o ring I used though. I have a kit but I can't remember if I was able to use one out of it or I may have ordered some from Mcmaster Carr to get a better fit.

The output seal wouldn't be bad to change but IMO that clutch seal with that ridge would be a bastard to change without splitting the cases.