Here is an extract from a book on two stroke engine modification/design:

"While on the subject of bore/stroke dimensions, I would like to say that there is
much in favor of long stroke two-stroke cycle engines in many applications. They are not
superior (as many people seem to think) compared to the present day short-stroke designs
in terms of low-speed torque, as torque is entirely a function of displacement and bmep,
and wholely unrelated to bore/stroke ratios. With a long stroke, there is (at any given
displacement) a reduction in bore, and with it a loss of piston area against which gas
pressure can exert its force, that exactly balances the loss of leverage in a short-stroke
engine (which is, in turn, compensated by a gain in piston area). The only thing wrong
with the long-stroke engine is that its crankshaft speed is limited by inertia loadings, and
that in turn limits its absolute power potential as compared with the “modern” shortstroker.
On the other hand, it is compensated by having a much more compact
combustion chamber, which makes for more efficient burning, and by lower thermal
loadings on the piston as a result of the smaller crown area into which heat from the
combustion process may soak. Finally, there is an advantage in port area for the longstroke
design resulting from its relatively large cylinder wall area. This area increases in
the long-stroke engine because displacement rises only in direct proportion to stroke, but
is increased by a factor of 3.1416 (the constant, π) with enlargements in bore. These are
very real advantages, but they are not enough, usually, to prevail against the short-stroke
engine's sheer ability to rev. Crankshaft speed is the only thing subject to much juggling
in the horsepower equation- and is a far more potent factor in determining power output
than the relatively slight improvements in bmep obtainable with the marginally better
combustion chamber and porting in the long-stroke engine. A 10-percent improvement
in our Kawasaki F-5 engine's bmep (a large improvement indeed) would raise its output
to 52.3 bhp; leave the bmep unchanged, but shorten the stroke and spin it 11,000 rpm and
you would have 61.3 bhp. There is indeed no substitute for revs."