Vespa Small Frame Overview
Small Frame Overview
The small frame casing was retrofitted to be able to carry an electric start function similar to the large frame system. The difference is that the starter motor runs straight through the casing to connect to the flywheel ring gear. The only different parts that consititute the electric start system are the cases, the starter motor, and the flywheel. Everything else within the motor is the same as a non electric start motor.
Standard small frame cases are shown
above - click for a larger image
All new casings come with a starter area
cast in to them, although if the motor was not electric start to begin
with the casting has not been machined around the starter hole, and the
hole hasn't been drilled - click for a larger image
The starter motor:
Above is a shot of the extending gear
called a bendix gear, which raises as the electric start motor is
turned. It has enough travel to engage with a flywheel mounted ring
gear when activated, and then drop down after the engine is turning.
The flywheel is very similar to a normal
flywheel except that it has a friction fitting ring gear all the way
around the perimeter. This gear engaes with the starter motor gear when
the bendix gear pops out of the starter motor..