H
i, folks. Two-strokes.
Now there are two
words that will
polarise opinion
among motorcyclists. There
are those who reckon they’re
the duck’s guts and those who
reckon they’re stinky, noisy and
outdated. I’m in the former group
but totally get the reasoning
behind the la er group’s position.
Yeah, they are smelly. It’s just that
I love that smell.
In fact, if you turn to page
18, you’ll get a rundown of how
Suzuki’s race program got hold
of performance two-stroke
technology. It’s a fascinating story.
Anyway. So why the hell is
two-stroke technology so out of
favour? A er all, two-strokes are
simpler and lighter and produce
about twice as much power as
four-strokes of similar capacity.
Well, there are a few salient
reasons why the technology that
gave us the thrills of watching
blokes like Fast Freddie Spencer,
Kevin Schwantz, Wayne Rainey
and Mick Doohan trying to tame
those wild and woolly 500cc GP
beasts dipped in popularity.
First up, two-stroke engines
don’t last nearly as long as four-
stroke engines. The lack of a
dedicated lubrication system
means two-stroke engine parts
wear a lot faster.
Two-stroke engines do not use
fuel effi ciently, not by a long chalk.
And here’s the biggie. Two-stroke
engines produce a lot of pollution
— so much, in fact, that this alone
has just about sounded the death
knell for the technology.
The pollution comes from
two sources. The fi rst is the
combustion of the oil. The oil
makes all two-stroke engines
smoky to some extent and a badly
worn two-stroke engine can emit
huge clouds of oily smoke.The second reason is less
obvious. For those who may not
be familiar with h ow it all works,
each time a new charge of air/
fuel is loaded into the combustion
chamber, part of it leaks out
through the exhaust port. That’s
why you see a sheen of oil around
the exhaust of a two-stroke. The
leaking hydrocarbons from the
fresh fuel, combined with the
leaking oil, means a real mess for
the environment. And that ain’t
good, in anyone’s language.
Now there is a fairly credible
view suggesting that, with the
right research and development,two-strokes could be “cleaned up”
to meet ever-tightening emissions
standards. But — and it’s a pre y
big but — that would be expensive
indeed. Why would manufacturers
spend the sort of money such an
undertaking would demand with
no cast-iron guarantee the result
would be totally satisfactory?
With four-stroke emissions far
easier to control, the bikes and
powerplants are well developed
and already in existence; the die
is cast.
Toss in the Global Financial
Crisis that saw motorcycle makers
(particularly the Japanese) tightentheir belts to the last notch and
the day of the poor old two-stroke
day was all but done.
Dirtbikes are still being
produced using engines that
employ direct fuel-injection
systems that are defi nitely cleaner
and a damned sight more effi cient
on a power basis than four-stroke
equivalents and the tech has some
applications that will keep it alive
for a while yet. But we’ll never see
the likes of Mick, Kev, Wayne and
Freddie again. Sadly.See you on the road,
GregDIFFERENT STROKES
GREG LEECH“Two-strokes are simpler and lighter and produce
about twice as much power as four-strokes of
similar capacity”
r Sadly, we'll never see the mad antics of the 500cc GP bikes in anger again.8 | AUSTRALIAN ROAD RIDERSNAGGED
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