Yanmar RS1400? That is the model that was sold together with YM2000. I think the decal on it specifically mentions YM2000.
I used mine the other day. Simple, indestructible, works as expected.
Try to get it with its special double-jointed upper link. The part nearest the tractor attaches with pins through both upper-link attachment holes on the tractor and extends back, rigid, half way to the tiller. Then there is a short specialty upper link to go the rest of the way. This keeps the tiller away from the tires when you lift it. If somebody used an ordinary top link with it then it may have hacked, extended lower 3-point attachment points.
Yanmar used these without a slip clutch, counting on it to bounce up and climb over an obstacle. This makes American users nervous.
If you don't have an overrun clutch the spinning tiller could push you forward by inertia. Again, these aren't standard for that tiller.
And if you add either a slip clutch or an overrun clutch then putting the tiller behind a Quick Hitch might be simpler than shortening its driveshaft. This would also make more tire clearance if you didn't get the special top link.
Buck (EFC) said the bearing on the offside gets no lube and on a 30-35 year old tiller like this, could seize up and cause expensive damage. He recommended replace it with a sealed pre-lubed bearing. It's a standard size that any bearing house should have.
Replacement tines are expensive. It should till ok with a couple broken but beyond that, consider the cost of tines in your total cost. Mine has the tips broken off two and I can't tell the difference. A dozen or so new spares were included when I bought it, but I haven't seen a need to install any for my very occasional use.
My YM240, a twin to the YM2000 these were sold with, of course runs it fine. This year I tried it behind the smaller YM186D. (US equivalent to YM1510D). It lifts it fine. I was running in quite dry ground and it was too much load to let it find its own depth, I had to adjust the draft stop to take a 3" cut. I was doing the tight spots where the 8 ft disc couldn't fit at the edges of the orchard, and when I sunk the tractor's tires into the 6" loose earth where the big disc had gone, the tiller would get too much bite and stall the YM186D.
That's all I know. In summary, recommended.