clutch rattle?


When my bike is idling, not moving, there is a rattle of sorts. It goes away (for the most part) when the clutch lever is pulled in. It has done it for about the last year but has gotten louder recently because: (posted on the "other site")

I (had to) replace the main bearings this winter. During disassembly I had missed the fact that the nylon drive and driven gears for the water pump were galling, but only a few teath on each gear. Being in a hurry I still reassembled with those gears. The 2nd thing I did wrong was to not mark the clutch basket halves when removed for exact reassembly (plates and discs also). The plates and springs are all on the low side of specs but not below. There is no noticeable wear on the basket. I am wondering if the clutch basket is out of balance now or the nylon drive gears are causing the noise. As said, it happens when idling sitting stationary and pretty much goes away when the clutch is disengaged. It is more noticable on my bike since before I had it apart. So,
1, Excessive clearance of the plates in the clutch basket?
2, Water pump drive gears?
3, Clutch basket support bearing going bad (I didn't remove this bearing, thought the noise was the crank bearings after they seized up)?
4, Clutch basket/plates out of balance?
Thanks to any replies,
'00 XC250