I think you're on the right track(s) Tyler.
Several factors must be at play to justify such an outlandish ratio.
G'day
MF,
Max and
TylerInteresting enough discussion on the Imperial 2-stroke.
Certainly on the right track except ...
I think engineer
Grumpy was on to it back in
2015. He looked to
causality in design as only a gifted engineer would.
I have included that link below.
I think the 80:1 mix was a
byproduct of another engineering
imperative.
Tracing the causality goes, for me, something like this ...
For the first 6 or so years, the
Imperial was powered by a 4-stroke. Why?
I mean, Victa had their horizontal industrial 2-strokes. Why not use them?
Best guess: Victa knew there were problems in mating a powerful
2-stroke to a small centrifugal clutch. Two-stroke power impulses are way
more pronounced than the 4-strokes of similar capacity and primary clutch
engagement would have been 'clunky,' to say the least.
By the late 1960s it seems clear that Victa were aiming for self-sufficiency;
in wanting their own 2-strokes to offer decompressors and recoil starts.
The key design feature is the lower compression ratio for the Imperial.
That smoothed the impulses to an acceptable level (with a smaller,
redesigned clutch).
This created another by-product issue - too much oil!
Best guess: Victa recommended BP Zoom
Outboard but the engine
ran so cool that an 80:1 mix was acceptable.
I also note that the Imperial was never fitted with a G4 carby. Victa
stayed with the ol' reliable G3. Why? I think Victa intended the
Imperial be retired the following season.
LINK:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=62325Cheers-------------------
Jack
