BTW, I had a broken weight on one of my keys. I think one of my kid's friends was playing the keyboard with his fist. I also had the case of the sqeeky keys. I looked into graphite and sprays to fix the squeek, and couldn't find anything.
The solution for both was to have the entire weight set replaced. I had that done and the battery replaced for about $250 in Portland, OR. I'd swear that even the stock samples sound better! The feel is much smoother and even between keys now.
Accodging to the technician (which sounds beneath the guy - he's an expert in the repair of classic organs), Kurzweil/Fatar updated the specs on the weight assemblies (3 for the 88) a number of times over the life of the product.
Anyway, if your keys are a squeekin', you might consider having it refurbished. Mine now plays much nicer than anything that I could have bought for $250.