85-87 ATC-R or 85-87 ATC350X.

The 86/87 R has the pro-link rear suspension and are the BEST riding trikes around. But they fall short because the forks blow super easy and are about like our LT rear shocks.

The X is a TORQUE. FREAKING. MONSTER. Talk about LOW. END. and they will stil ru! like a **** ape up top!!!

Since you would be a first time trike I recommend those (and mostly the X) so you can learn on them.

And then you get an (85) A1 or (86/87) B1/B2 Tecate 3.

A1 has the fatty front tire, non-KIPS engine and are WICKED MEAN.
The B1/B2 have the KIPS engine and the saddle mount rads.
The Tecates actually handle MUCH better but have a LOT more power than the Hondas. They are violent. And there's still LOTS of aftermarket support for them. Everywhere from big bores to pipes.
They are bad about the rear shocks like our Suzuki's.

The Tri-Z 85, 85.5, 86 Tri-Z is a larger machine. They fit a bigger/taller guy better and with a good port, rechambered head, good pipe, carb combo they will run with the wicked Hondas. Harry Klemm is building 346cc big bores for these again. That's 346cc on stock stroke as well. >:]

I'd recommend a first timer getting a 350X or 85/86 R (you aren't goin to find an 87 R or X but they DO EXIST. It was recently confirmed by Honda Canada that they sold some true 1987 model units)