PART TWO - Detail of New Models
I include here detail summaries of the five new models.
It is clear that 4-strokes were making a huge impression - even at
Victa Mowers.

The biggest 'new' feature' was the, "New Trans-flo cylinder for extra power".
This was reference to a radical change in the 125cc engine barrel. The design
removed the transfer port covers that Victa had used since its 1955 Model 1.

That change was of some significance, and I asked for expert opinion from
Global Mod Gadge:-

"The change to the 125's transfer ports was much more than just removal of the
port covers. It involved a fundamental change of the shape of the top end of
the port, with a radical effect on the gas flow path/s and velocity of the
incoming air/fuel charge.

The original top transfer ports were just two roundish holes in the cylinder
wall. Downright crude, from the engineering standpoint!

The new transfers were an 'inverted L' shape, so that the incoming, opposing
gas streams would swirl around the combustion chamber as the charge got
compressed, approaching TDC.

It's all about gas turbulence, to promote efficient combustion, and therefore
maximise power output.

The 'squish band' piston/combustion chamber design combination as used with the
almost flat-top Victa 160 piston achieves much the same thing, just in a
different manner. Even though the band is only small."

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