Hi All,
I had the clutch drag when I bought my 315 also, here are the three things that fixed mine totaly.
1 Drained the gear box oil and refilled the correct amount of Dextron ATF rather than the elf oil. Be warned this is not the specified oil for this bike, it is just my personal view.
2 Bleed the clutch using a long tube into a bottle and getting the bike high as possible and the bottle low as possible sets up a gravity feed and is the best easy way of fast flowing fluid to remove any air, don't be shy with the fluid an extra