As Tom said...you could've left out the metal sphere that is inside the clutch axle so check it!
If it is there you'll need to recheck the "buttefly" nut that is at the end of the clutch basket.. it is surely too loose or too tight..
It took me a few times opening and closing the engine casing just to make it perfect!
And DON'T forget, after the engine is full of oil that messes the clutch play soo it needs to be just a wee bit loose!
Also... after you set the butterfly just a little loose, you will adjust the clutch play at the clutch LEVER "on-the-fly" adjuster or you just won't be able to make it work!
Soo. setting the clutch, the "on-the-fly" adjuster should be at middle position! THIS IS IMPORTANT! or you won't be able to adjust the clutch!