The main difference between the non-electric start PK Automatica motor and the electric start one is the starter motor and a special flywheel that has gear teeth around the outside. The casing from the non electric start motor can be modified pretty easily to fit the starter motor.
The casing starts out the same
when it is initially cast. On motors designated to be kick start only,
Piaggio doesn't bother machining the starter motor hole or the threaded
stud holes on either side that hold it in place.
All you need is a drill press
and a hole saw to make the hole. The casing in this shot was stripped
of all bearings so that none of the aluminum bits could get in and ruin
things. I found the center of the area (just about), and bored the
whole through the casing. It is important to make sure there is a lip
(or shoulder) to the hole so that the starter motor has something to
stop it pushing straight through the hole.
The next step is to drill out
some holes for the studs which will hold the motor in place.
The factory motor comes with
studs that are screwed in to the casing. I found it hard to find the
rights studs so I just drilled straight through the casing and I will
use bolts instead.
I also found that when I tried
to test fit the starter motor the inside diameter of the hole and the
outside diameter of the motor didn't fit. I had to remove about 1mm all
the way around the perimieter of the hole. Once I was done, the bolt
set up and hole look almost like a stock motor.
The motor is bolted in place
with 2 nylock nuts so they won't shake free.
The final part of the puzzle
is to relace the existing flywheel that came with the motor with one I
found on eBay Germany that is specific to the automatica motor. The
PK80 Automatica and 125 Automatica share the same flywheel but the 50cc
version is very different and won't work with the drive pulley.