Modern Vespa

I am getting ready to install the motor/engine into the Vespa. I'm not sure of the best way. I have laid the Scoot on its left side and installed the motor that way. It worked pretty well except I should remove the cowling first which involves accessing the small hard to get to nuts that also involves removing the gas tank that also involves wrestling with the fuel shut off.
The other was is to elevate the rear and install from underneath. This method is not very steady and is very back heavy. I'm not sure how to stabilize front to back and left to right during the install. Also I should note, I am by my self so no other hands are available. Any ideas from the forum?

I just put some 2x4 under the center stand. Run a strap from the center stand around the front to the other side of the stand so it can't fold up. Prop up the back. Slide the engine into place, tilt up to the swing arm and bolt it up.
I always work alone. I now use a work table that I can strap the scooter in place

Grump's way sounds good.

Personally I do like the reliability of a front wheel chock in addition to a pair of jack stands under the frame's rear end and sturdy blocks under the center area. Typical HF motorcycle lifts that have a chock are great in this regard, and you'd obviously have the front fork and wheel installed before stuffing the motor into the frame. Add some ratchet straps too.

I'd say, without a lift or table, just improvise with as many of the above components as you can utilize.

Pics are from a couple of restorations ago, and I'd recommend adding straps:

If you can set it up to do it on it's side, it's by far the easiest method. But yes, difficult to protect that side panel.
Usually I do it Grumpnut's way.

Recently though I found that it's easiest to put the rear shock bolt through first, then lift up the front of the motor until you can get the big bolt through. This method also means that you can fit the exhaust before the motor is in the frame. It seemed to be much less hassle that way.

i'm with grumpnut. move that thing under there and tilt up the swingarm. stick a screwdriver or whatnot into the frame hole and the swingarm, then once it's stable, you can deal with the real bolt, which takes a bit more finesse, since it's so close of a size match.

sometimes it's nice to have a wheel on to make it easier to maneuver.

+1 grumpnut

You'd be surprised how much space a small block of 2x4 under the center stand can give you.

I have a transmission jack and an ATV jack and thought I was a big deal. I could not install the engine this way and my attempts were pure comedy.

Did the wood blocks and tilt
up the swing arm and it worked perfectly.