JD650 update....
I found a few salvage yards that had a clutch for the 650....but some wanted north of $1000 for the clutch
John Deere no longer makes this part for a machine made in 1986....Really ticked me off, as like you would think Deere parts we all thought would be available....nope. I was told to check with Yanmar, then Yanmar told me to get with deere.
I did finally find one at a local salvage yard for only $400...it was a used part....but what are you going to do. I then went back to the dealer to order some parts for the "mule drive" the pully system under the PTO....Bearings belts and such. Finding those parts took the dealership 2 days, the mower deck and mule drive are not listed with the tractor....but they did find them. I have all the new parts installed, 2 drive belts, 1 new idle pully, and a couple bearings that I needed to press in and it all works great. The dealership really came through finding the deck drive parts. So I am belly mowing again, but OMG what a pain.
Moral of the story is Just because it is Green Orange Red or PINK it does not mean it will still be made even 30 years later. The tractors are built to last, but you might be needing a machine shop to keep everything working. The thing that really got me was the finger pointing....talk to Yanmar, but the tractor says John Deere, yea but it is a Yanmar tractor....call Yanmar...No we don't have parts for it, talk to Deere. Then in buying a new machine....this 1 series that is a Deere....but the engine says Yanmar....yea but it is a Deere....funny that is not what your parts guy told me, they told me Yanmar built it and Deere just painted it green and slapped a sticker on it....oh, well it is not that way now.
So I bought a Kubota, they make the engine, and most bits in the machine. I am sure there are sub sources in the machine, but it sure does not have other peoples engine in it.