KTM forced Kawasaki and
Yamaha to improve or disappear (as Suzuki and Honda had).
Fortunately for kids around the
world, the KX85 and YZ85 were
finally updated. The 2015 Yamaha
YZ85, which we tested in the
June 2015 issue, is an improvement over the previous generation. Unfortunately, the updates
weren’t enough to satisfy our
fickle mini-cycle testers. The 2015
Yamaha YZ85 failed to meet key
performance objectives, particularly with respect to the engine
and suspension. That’s why MXA
asked Doug Dubach, owner of
DR.D and a tenured production
test rider for Yamaha, to shake
out the bugs on our 2015 YZ85.
Dubach addressed the weak areas
in hopes of producing a project
bike that could stand up to the
powerful orange tide of KTM mini
cycles.
ENGINE: The new intake and
exhaust port timing on the 2015
YZ85 helped increase power in the
midrange and top end, but that
was just the start. Dubach had his
longtime friend, Dean Dickenson
from R&D Racing, mill 0.010mm
off the cylinder head. The idea
was to raise compression, but not
so much that the YZ85 couldn’t
still run on 91-octane pump gas.
Doug then searched for the best
pipe and silencer combination.
He had his son, Carter, test every
aftermarket system he could get
his hands on. You’re probably
wondering why Dubach didn’t use
a DR.D exhaust. That’s simple:
DR.D doesn’t make a YZ85 pipe
and silencer…yet. Carter preferred
the HGS/Bud Racing pipe and
silencer because they made more
power everywhere without any
trade-offs.
SUSPENSION: We stated in
our test of the 2015 YZ85 that,
“The Kayaba suspension should
be fine-tuned for more real-world
function.” Dubach didn’t turn a
blind eye to our complaints. He
had Enzo Racing service the YZ85
forks and shock. The spring rates
were in line with Carter’s weight,
but the damping was off. Enzo
increased the damping for a
more aggressive feel. Carter
Dubach was impressed with the
changes, because he could ride
more aggressively. Doug was
happy that the improvements
didn’t cost an arm and a leg.
BRAKES: Milling the cylinder
head, tacking on an exhaust sys-
tem and changing the suspension
valving are normal for most racers’
modification programs. Taking a
part off another bike and retrofit-
ting it to our project bike? That’s
not as common. But, Doug Dubach
discovered that he could use the
rear-brake master cylinder from a
YZ250 two-stroke on the YZ85
caliper. More fluid meant better
braking power, which is some-
thing the YZ85 desperately needs.
Doug Dubach also made a front-
brake-line clamp that attached to
the fork guard. Coupling it with a
shorter Galfer brake line, Dubach
was able to route the brake hose
for a more direct path to the
caliper. The stock brake line hides
behind the left fork guard, wraps
underneath the fork lug and
makes a 90-degree bend into the
caliper. This round-about design
hinders oil flow, which makes
brake performance suffer. The
DR.D YZ85 front brake was consid-
erably stronger due to the brake
hose’s rerouting and Galfer Wave
rotor. Good stuff.
ACCESSORIES: The DR.D
Yamaha YZ85 came together with
the help of longstanding Dubach
supporters. Doug chose a DT1 air
filter, Talon sprockets, Motion Pro
rim locks, a Hammerhead shifter,
Maxima oils, Pro Taper handle-
bars, ODI grips, Dunlop MX32
tires, Dubya wheels, Excel rims, a
Motoseat cover and DeCal Works
graphics. Most of these parts
were creature comforts for Carter
