Two-stroke or four-stroke? That’s the age-old question for a motocross racer. The
general consensus is that four-strokes
are popular with more people, but
two-stroke riders are more passionate. It’s no secret where the
allegiances of the manufacturers
lie. Only KTM, Husqvarna, TM and
Yamaha still believe in two-strokes.
As a result, the landscape of
motocross has significantly changed
in the past 15 years.
Two-stroke aficionados consider
1993 to be the pinnacle of a technology that was quickly overshadowed
by a boom in four-stroke development. Why 1993? That was the last
year that such mythical beasts as the
Kawasaki KX500 and Honda CR500
had a place in motocross
racing. After 1993 the AMA slew
the mighty dragons by terminating
the oldest and most prestigious class
in American motocross. You would
have to take a ride in Mr. Peabody’s
way-back machine to visit the time
when the iron men of motocross,
such as Mike LaRocco and Mike
Kiedrowski, raced the 500 Nationals.
Champion in a class that quickly lost
relevance. For a time after the AMA
dropped the 500 National series,
bikes like the KX500 and CR500
were still sold, even if they were
warmed-over designs from a bygone
era. Eventually, however, Honda
(2001) and Kawasaki (2004) stopped
producing 500cc two-strokes. These
days the ancient relics are buried
in deep corners of garages and can
be purchased for a nominal price on
Craigslist.
Sean Collier was born 20 years too
late. The blue-collar, part-time AMA
National Pro is the quintessential
500cc two-stroke racer. He’s able to
harness the power of a 60-plus-horse-
power, 500cc two-stroke like a lion
tamer. Collier’s talents are even more
impressive considering that he works
a 9-to- 5 job as a water-treatment specialist and still goes mind-bendingly
quick around an AMA National track.
He is the very essence of what all
“Average Joe” racers aspire to be.
Sean clocks in 40 hours a week at
a day job and can stay on the same
lap as Ken Roczen. Most unbelievable is that Collier can crack the top
20 at a 450 National and then
dominate a field of two-stroke
specialists on his father’s 1997
Kawasaki KX500—all in the same
day. Sean Collier is a special
pedigree of old-school manliness
mixed with new-school speed.
Collier’s talents were on full dis-
play at the second round of the AMA
Nationals where Glen Helen hosted
the FMF Two-Stroke Challenge exhi-
bition race along with its normal
250/450-class duties. Sean quali-
fied for the 450 National and was
oh-so close to scoring points, going
21-23 for 25th overall on his C4MX-
built 2015 Kawasaki KX450F. He
redeemed himself by stomping the
field in the two-stroke race on his
trusty KX500. The MXA wrecking
crew cheered Collier on as he pow-
ered up the hills and launched every
jump on the vintage iron. Sean’s
fluid style on the monster two-stroke
harked back to the summer of 1993.
Naturally, we wanted to get a piece
of the action, so we decided to
test Sean Collier’s KX500 and his
Kawasaki KX450F. Here’s what we
learned about each bike.
SEAN COLLIER’S
2015 KAWASAKI
KX450F
FOUR-STROKE
For a privateer, Sean Collier has a
phenomenal race bike. His Kawasaki
KX450F is blessed with a variety of
purposeful products that aren’t the
garden-variety sort. Need proof? Look
no further than the oversized car-
bon fiber gas tank, titanium radiator
catch tank, razor-sharp Raptor tita-
nium footpegs and a sleeper engine
KX500 TWO-STROKE VS. K
C4MX resurrected
Collier’s KX500 by
pouring time and
effort into a worthy
machine. The results
were outstanding.
