[stay_upright]

I think you will find a lot of resistance comes from the oil when you re-oil the clutch but this can still be made worse with slightly warped clutch plates etc.

With my old clutch I could see the plates were warped by putting them on a mirror and looking at them.

As an experiment maybe try a thin oil - I don't know what the thinnest oil is we can safely run in these bikes though? I don't think anything will fail catastrophically but probably accelerate wear. I guess ATF fluid is pretty thin (a lot thinner than standard oil) (can't remember if you have tried that already) if not maybe try a thin ATF fluid.

Is it a dead engine racing start you are having trouble with or trail riding?

On a note the make up of the clutch means if some plates and steels are stuck together with oil and you pull the clutch there is nothing to pull all of the plates apart i.e. only one pf the plates/steels needs to seperate and the reast can stay stuck together and provide quite a bit of resistance when you kick it.. ideally a multi plate clutch shoudl have little springs between each friction and steel so when you pull the clutch they are all pulled apart evenly and none will remain stuck together so they can't drag... I wonder if the order you are putting your steels/plates in is having an effect?