Kawasaki kxf 250 is leaking oil from the back of the front sprocket how hard is it to fix problem

You're problemme is the counter shaft seal is leaking....this is the seal right behind the front sprocket....i tough there is also a inner o-ring on that model that you shall have to change...thank you for leaving good feedback.

The sprocket sholdn't contain any oil. Its probably the brakes or your shocks/dampers. It needs to be replaced or seals fixed. Confirm what the fluid is prior to repair.