HOW DOES COST COMPARE?
If you want a sport quad and money
is an issue, the $6399 400X is easier
to reach than the $7799 450R. For
recreational riders, the 400X will likely
be less expensive to maintain as well
since its less highly stressed, air-cooled engine requires less frequent oil
changes and will never need a coolant
HOW DIFFERENT ARE THE ENGINES?
Very different. Both are carbureted,
engines, but the 400X is less
sophisticated and far less highly tuned.
The 450R is designed to rev quicker
and higher, so its piston and crankshaft
are far lighter than the 400’s, and its
bore is much larger than its stroke.
The 450’s cam opens the intake valves
directly to eliminate the weight of
rocker arms for better control at high
revs. Liquid cooling helps manage the
extra heat the high-performance 450
The 400X’s air-cooled engine has
an oil cooler to dissipate excess heat,
and it uses rocker arms to operate its
four valves. Even though the 400’s
compression ratio is much lower than
the 450’s— 9.1:1 versus 12:1—both
machines require premium pump gas.
WHICH ONE IS FASTER?
The 450R, by a huge margin. The
beating the 450R put on the 400X in
our drag race tests says a lot about
why the 450R is the preferred machine
for all kinds of racing. That’s not to say
the 400X is slow. The 400X is a sport
quad with serious performance; it’s just
not as blisteringly fast as the 450R.
HOW DO THE MACHINES’ POWER
DELIVERY COMPARE ON THE TRAIL?
These two machines have very
Both machines are
responsive and powerful,
with more than enough
performance to slide or
wheelie at will.
different kinds of power. The 450R
revs faster and higher than the 400. It
also makes more power and responds
instantly. The 400X is responsive and
powerful, but it’s much more smooth.
The 450R’s power advantage made it
faster in easy, open terrain; on big hills;
and even on tight, difficult, technical
trails—for our pro racer. Most of the
time our trail rider was as fast on the
400X as on the 450 because he wasn’t
using all the 450’s power. When we hit
the tougher parts of the trail, the 450’s
abrupt power actually slowed our trail
The 450 is harder to control at
very low speeds, stalls more easily
and doesn’t pull from a dead stop as
smoothly as the 400X, which made
the twisty, rocky uphill canyon trail on
our route tough for our trail rider when
he was on the 450. The 450 doesn’t
have reverse like the 400, which makes
tackling some tough situations extra
HOW DIFFERENT ARE THE
About as different as sport quad
suspensions can be. Both machines
have double-A-arm front ends and rear
swingarm suspension, but there’s a big
difference in the shocks. The 450R also
has .2-inch more travel front and rear.
The 450R has piggyback reservoir
shocks with adjustable compression,
rebound and spring preload front and
rear. The 400X has a fully adjustable
piggyback reservoir rear shock, but the
front shocks have no reservoirs and are
only adjustable for spring preload.
HOW DID THE SUSPENSION WORK FOR
This was interesting. At a glance, the
450R’s suspension looks superior, but
how the suspension works for the rider
The 450R’s liquid-cooled engine revs faster and higher than the 400X.
It also responds instantly and makes more power than the 400X.
The air-cooled 400X is responsive and powerful, but its power delivery
is much smoother than the 450R’s.