Yep that's the twin to my RS1400. Mine looked more weathered than that when I bought it in about 2006. I had asked for the cheapest one they had. Surprisingly, included for the $200 was a set of new tines. I've never needed to install them. It has always been reliable, I got a bargain.
I went all through the tiller today. Drained the inevitable condensation water (couple of ounces) from the bottom of the gear case. Opened and checked the bearing on the far end of the tine axle, that I had replaced in my initial setup. Fluid levels ok. Lubed the driveline expansion joint so now it slides easily, it had been gummed up. Likewise the unlock pins at each end of the driveline, and the tailwheel swivels. All had been gummed up and stiff. It's been a while since I maintained it.
And I tried mounting the tiller with just the YM186D's normal top link instead of the special 'bridge' needed on the YM240 that gets the tiller clear of the tires. This works, after adjusting the depth wheel to lift the 'training wheels' as high as possible. I may not be tilling full depth but the little YM186D (15 PTO hp) is working hard, needs full throttle and still can't hold rpm occasionally, so this is as hard as I want to work it.
Then I went out and did something boneheaded. Tilled blackberry jungle without mowing it first.
This got so many canes snarled around the tines and shaft that it took hours to take them out. I'll start another thread here with a photo, titled something like 'Don't Do This!'
