his pipe received universal
acclaim. It scored three first-
place rankings out of four—and
the fourth rider ranked it second.
DR.D has a reputation for building
awesome Yamaha YZ450F exhaust
systems. This might be because
DR.D owner Doug Dubach was the
Yamaha test rider who developed all
the Yamaha’s four-strokes—from the
1998 Yamaha YZ400 on up to the
current model.
WHAT WERE THE MOST
COMMON TEST-RIDER
COMMENTS?
“This was the best all-around pipe
of the five. It did everything right
from the bottom through the middle.”
“The DR.D pipe produced the best
midrange power. It felt crisper than
the other pipes.”
“This would be my choice because
it felt torquier from the bottom to
the middle. It doesn’t have the
irritating bark off the bottom that
the stocker has, but is the strongest
where it counts.”
“It was fairly seamless through the
middle. Best of all, it ironed out the
DR.D NS- 4
first breaks 50 horsepower at 7400
rpm. This is 100 rpm later than the
stocker’s 7300 rpm.
RETAIL PRICE
$599.95 (stainless/aluminum/
magnesium end cap).
CONTACT INFO
www.dubachracing.com or
(877) 382-2241.
flat spot and dip in the stock
powerband. It was the most raceable
of all the pipes.”
TEST-RIDER RANKINGS BY
SKILL LEVEL
Pro: First
Vet Pro: First
Intermediate: Second
Novice: First
DR.D NS- 4 DYNO NUMBERS
Here are the DR.D YZ450F dyno
numbers.
rpm ..................................horsepower
5000 .................................................... 25. 55
6000 .................................................... 37. 11
7000 .................................................... 47. 34
8000 .................................................... 53. 61
9000 .................................................... 59. 90
10,000 ................................................. 58. 88
Peak............................ 59. 50 9700 rpm
DR.D NS- 4 TORQUE NUMBERS
The DR.D exhaust produces 35. 99
foot-pounds of torque at 7400 rpm.
This is 0.23 foot-pounds more than
stock. The DR.D pipe makes the
most torque in this test.
WHEN IT BREAKS
50 HORSEPOWER
The DR.D YZ450F exhaust pipe
T
