You are correct in your assumption. Kicking it over spins the rotor and also the crank flywheels all of which pick up oil and throw it up and back into the gearbox area and raises the oil level where the window is.
Nothing to do with the pump and you you would have to be kicking at some speed to get any oil pressure.
Thanks for this illustrated explanation. I've not had cause to dig into the case. Just to check I've understood it:
- The chamber shown on the RHS of the top picture, is this sealed off with a gasket and blanking plate, so oil circulates within?
- What is the purpose of that chamber, is it solely to supply the oil pressure breather vent at the top?
- How is the gearbox supplied? Is it just that passage under the selector shaft, sharing oil with a gearbox sump?
- Mine is a later bike with a second, front drain plug. Essentially, is that the only difference in the casing?
Many thanks,
Martin