It's really easy to do by hand, just go slow and don't use any force.
Set the ring gaps to the right positions on all four pistons, then set 2 and 3 at TDC.
Make sure your base gasket is in place (I forgot once...)
Put a piece of wood between one of the (2 or 3) piston skirts and the engine case.
Slide the barrels onto the studs, gently settling on the two pistons, working the piston tops in square. The block will slide down freely until the compression rings meet the tapered bottom opening of the cylinders. Now press a ring into its groove using tour fingertips and nails, starting opposite the gap. By gently pressing in the ring while rocking the piston a bit, the ring will compress and enter the bore. You have to work the two pistons alternately a little bit but it sounds harder than it is. Then once both compression rings are in, work on the oil control rings and finally the oil rings. Slide the bores down until the rings are all past the taper, but not really deep in there. The further in you go, the lessroom you have for working on the 1 and 4 rings.
Pull the wood block out and turn the crank slowly while making sure the cylinder block moves down the studs along with the 2-3 pistons. The 1 and 4 pistons will also be moving up, and when they meet the cylinders you just repeat the ring insertion like on 2 and 3.
I've tried the official Honda ring compressors, hose clamps, and some other small engine ring compressors: they all were more trouble to install and remove than they were worth and the whole job was faster and easier with just fingers. If you're ham-handed or really impatient with fiddly things, use compressors - you CAN snap a ring with this approach if you get too physical or frustrated.
