If it is the detent spring then its about a 4 hour job unless you have done it before then you can easily shave between 1 to 2 hours off that as long as you have all the parts needed. Spring, Gaskets, Clutch hub nut and as long as your in there you might as well update the lifter piece and throw a new lifter shaft in her for good measure. You might not need the lifter shaft but at the price you might as well have it handy. Myself I would change the fibers out while you in there but to be honest if the clutch is not slipping in 5 th gear when you roll her on hard I would not worry about it. It depends on your wallet and how hard you plan on riding her. MTC make a great set of fibers which I have only been able to break two when my internal hub exploded.
When you change the spring do not use any tools like pliers or needle nose pliers. In fact you would be better off doubling 50 test fish line to stretch it on the post. any toll mark nicks will make the new spring fail prematurely. Also MAke sur eyou get the oil pump drive lugs lined up and in the back of the clutch basket or the clutch will not go completley ong the input shaft. You can tel it is not right because the clutch not will not go on the shaft far enough.
Hope this helps