ST70 semi auto-occasionally slipping kick

Howdy

This may sound like an ignoramus inquery but this is the first time for me to own a Dax.

out of 5 times the kick starter is used:

2 times - it will work perfectly (crank the engine all the way, starts the engine right up)
2 times - it will slip (have a 'smooth / strong' reisitance going down and engine doenst crank)
1 times - it will slip totally (have 'no' resisitance going down and engine doesnt crank)

I could live with it but want it to be perfect each time!
Any tips on where to start looking?
Thanks

- clutch tension (bolt at clutch side)
- condition of the clutch plates
- type and condition of the engine oil
...

Check the steel rollers etc. in the centre of the clutch, the ones that enable the kickstart to operate regardless of rotational speed

Thanks for your help!
Works like it should now!