test reports had been filled out. This is
important, because test riders can be
influenced by the opinions of other test
riders. Thus, we got the info before they
knew what the other testers thought.
( 4) We dynoed each pipe on the same
dyno at the same temperature on a
brand-new 2014 Yamaha YZ450F—and
within a three-hour window to ensure
accuracy. These dyno numbers are only
comparable to dyno runs made on the
same dyno on the same day.
( 5) We sound-tested every pipe combo,
but since every one easily passed the
AMA Amateur 94 dB standards, we
didn’t feel compelled to report the data.
( 6) Since we mounted and removed
each exhaust system many times, we
learned how each system fit together,
and, more significant, we learned the
importance of anti-seize compound.
( 7) We did not ask the pipe
manufacturers to send us their most
expensive units, because whether they
are titanium or stainless steel, the
dimensions and performance are the
same. The prices vary with material,
however, so we have included the prices
of all the 2014 YZ450F exhaust systems
that each company makes.
( 8) There is a caveat to every exhaust
pipe test: don’t be too enamored with
big dyno numbers. The dyno is just a
tool that allows us to gauge the shape
of the curve and get some comparative
figures, but it does not go to the
starting line with us. What really counts
isn’t which pipe makes the biggest
numbers, but which one provides the
most usable power, quickest rev, most
throttle response and best curve.
( 9) During our testing, we discovered
that different skill-level riders sought
out different types of powerbands. The
favorite pipe of the Pro test riders wasn’t
always the first choice of the Novices,
while the Intermediates always seemed
to seek the middle ground. Thus, you
have to have an inner dialogue with
yourself about what you really want out
of an aftermarket exhaust.
( 10) These are our results. The best
2014 Yamaha YZ450F pipe for you is in
here. Find it.
During our initial testing of the
YZ450F, the map we preferred to
use with the stock exhaust system
didn’t work with aftermarket pipes.
After more testing, we discovered
that the aftermarket pipes worked
best with the stock ignition timing
and slightly richer fuel mapping—
typically 1, 1, 1 on the bottom and
second row of the chart and 2, 2,
2 on the top row of the fuel-map
graph. In colder weather, you might
try 2, 2, 2 on the bottom two rows
and 3, 3, 3 on the top row. It should
MXA’S MAP FOR 2014 YZ450F
pipes from FMF, DR.D, Pro Circuit and
Yoshimura are designed around the
stock 0, 0, 0 maps.
5000 26. 47 25. 55 26. 79 25. 57 26. 40
6000 37. 80 37. 11 37. 51 36. 46 38. 22
7000 47.01 47. 34 46. 94 47. 15 47. 18
8000 53. 54 53. 61 54. 30 54. 46 54.04
9000 59. 35 59. 90 59. 89 59. 30 59. 23
10,000 57. 88 58. 88 59.04 57.04 59. 94
PEAK 59. 39 59. 90 60. 14 59. 30 60.01
STOCK DR.D FMF PRO CIRCUIT YOSHIMURA
2014 YZ450F HORSEPOWER BY EXHAUST SYSTEM