VOL. 54 ISSUE 44 NOVEMBER 7, 2017 P83
Gear ratios were a big discussion
point back at the truck with a lot of jour-
nalists in attendance quizzing Japanese
engineers on the tall-and-short of it all.
You should expect to see plenty of opin-
ions coming out with sprocket swaps.
We suspect there is a lot of tuning to be
done here, especially for those looking
for some torque or more of a hit down
lower in the rpm range. Of course, we'll
try to play with them, too.
Since Honda MX bikes come with
three fuel injection maps built-in, and
you can access them anytime via the
handlebar switch, we just had to try
them all.
Admittedly, we rode around most of
the day in the aggressive map. Zaca
Station's hills and deep soil made it an
appropriate place to do so. Also, from
our first impression, there is little to risk
in riding the 2018 CRF250R aggres-
sively.
The smooth map left the CRF wheez-
ing a bit too much—killing much of the
excitement of the midrange accelera-
tion into the forever top. But the stock
map was really good without the extra
midrange surge. Stock was not as fun
as the aggressive map, since it doesn't
have the same mid-to-top surge, but it
was capable at turning laps and clear-
ing jumps. In fact, we had the aggres-
sive map spin the tire on some freshly
watered sections where the stock map
was simply driving forward. So, the dif-
ferences are real.
The aggressive map setting was the
one for this day. The bottom-end and
lower midrange are nearly identical feel-
ing to the stock map, but the accelera-
tion through the mid is amplified in a few
spots in particular. This made it a really
fun ride off the drop-offs at Zaca where
you accelerate off a downhill edge. The
CRF would be really singing when you
hit them, and that alone was worth the
aggressive map.
DUAL EXHAUST
The engine features two totally indepen-
dent exhaust headers; each respec-
tively linked to either the left- or right-
side exhaust ports. There is no mixing
of exhaust gasses here. Once fuel is
burned and pumped out of the cylinder,
it is completely segregated past the
exhaust valves through pipes and until it
barks out the mufflers.
This seems odd on a single-cylinder
bike to many. But Honda staff and
project leaders pitched us on the con-
figuration as nothing but higher per-
forming. And here's why, in their terms:
As exhaust gasses flow past the valves
and come together in a single-pipe, or
traditional single-cylinder head, there is
resistance. Honda calls this friction.
According to Honda, independent ex-
haust gas routes like those on the 2018
Honda CRF250R eliminate this and
improve flow. Also, by bending exhaust
pipes around both sides of the engine
with narrower diameter tubing than one
