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Feature
DR650SE R&D
Phase III
by Dave Searle
C
fulfill completely different roles with only a
swap of wheels? Our answer is,
“Yes, indeed!” In past installments, we
fixed the big DR650SE’s worst problems
first (Phase I, Mar.’08), then converted it
for long-distance adventure touring
(Phase II, Nov. ’08). Now, we transform
our sweet 40-inch single into a firebreathing, corner carving supermoto.
AN ONE MOTORCYCLE
Suspension
In Phase II, we changed the DR’s front
and rear springs for Eibach parts, so it
was time to attack the dampers. Race
Tech’s Cartridge Emulators were an easy
DIY installation at home in the garage
($169.99/pair). The rear shock was rebuilt
at Race Tech’s nearby Corona facility,
utilizing the company’s high-flow Gold
Valves for superior control fitted with
revised shim stacks for increased damping rates. The shock rebuild process was
illustrated and described in our July 2009
article, “Affordable Custom Suspension.”
Total cost on the shock was $305.95.
The Emulators replace the stock fork’s
old-school compression damping system
of four drilled holes (which are multiplied
and enlarged so as not to create any
restriction) in favor of a spring-loaded
shim stack that’s housed in a separate cartridge mounted beneath the fork springs.
Compression damping is the most difficult function for a fork, so improvements
in this area promised the greatest improvements. Installation is a straightforward
task made easier by an air-powered impact
wrench to remove the bolts that hold the
sliders to the damping rods, and a step drill
to cleanly enlarge the stock holes and cre26
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ate additional large holes from small
diameter pilots. Care should be taken to
thoroughly deburr all the holes, particularly their inner edges, so that stray metal
particles don’t end up caught in the shims.
A Dremel tool fitted with a spiral round tip
worked well for this purpose. The existing
spring spacers must be shortened by
15mm to account for the height of the
Emulator cartridges, and we took this
occasion to readjust the preload. We had
used 80mm spacers and cut 11mm off, to
add an additional 4mm to the total set-up.
The Emulators and thicker fork oil
made a huge improvement in the front
end, actually improving high speed stability as well as delivering a more plush and
controlled ride. When the revalved rear
shock was mounted up, the improvement
was complete. The rear compression
adjuster needed to be set seven clicks
from full hard (just one out was our previous setting) and the rear end felt much
more planted, which actually aids front
traction as well, since weight isn’t transferred so strongly to the back with each
bump. On the trails, we could remain
seated where we’d need to stand previously to avoid back injury, and the bike
could be jumped and land in full control
(something it couldn’t do before). The net
result: We could ride faster with more
control and more comfort—outstanding!
greatly simplify wheel swaps. Parts
include the hubs, bearings, spacers and
seals which will run roughly $450/pair.
As the stock hubs are rough and unattractive, several hours were spent with a
Dremel tool, files and sandpaper improving their cast finish before delivering
them for powder coating. Note that the
powder coater will sandblast the hubs in
preparation, which will erase any tiny
scratches remaining from your handiwork. He will also mask the surfaces to be
left bare before applying and baking on
the paint, so you need to be clear about
instructions. Aside from the bearing and
bolt holes, the machined disc mounting
surfaces should not be coated, and on the
rear hub, be sure to leave the area that
holds the rubber shock dampers uncoated
as well (if you don’t, and I didn’t, the
hub’s fit will be very tight, although it
won’t prevent reassembly). The coating
was about $30 per hub, and cleanup of
inadequately masked surfaces took some
additional time. The powder coat paint is
very durable, but fairly thick, so you may
find that the spoke holes in the hub too
tight for the larger aftermarket stainless
steel spokes. An 11/64" drill was passed
through the holes that had a problem and
worries about paint chipping turned out to
be unfounded.
The painted hubs should be protected
from scratches during bearing installation.
Because the bearings are an interference
fit, the ball bearings should be placed in a
freezer beforehand and the bearing bores in
the hub should be greased and then
warmed with a pinpoint propane torch to
provide clearance. A deep well socket that
Supermoto Wheels
Although complete wheel sets are
available for the DR, we figured we could
save some money and do a nicer job by
building our own. So we purchased the
parts to assemble another set of OEM
Suzuki front and rear hubs, which would
MOTORCYCLE CONSUMER NEWS
Above: Race Tech Cartridge Emulators
were installed in the forks (an easy DIY
installation), and the shock was professionally rebuilt—major improvements.
Above: Because a proper supermoto’s wheels should be a thing of beauty, and stock roughly finished hubs were our only option,
we got out the Dremel tool, some small files and sandpaper to refine the surfaces before powder coating them a steel gray
color, which matched the DR’s color scheme. Note the finished hub: It should not have been coated on the damper vane section.
matches the outer race diameter will work
as a driver. With a heavy brass hammer
and careful attention to driving the bearings squarely into the holes, you can do
this at home. If you don’t trust yourself,
pay someone else to do it.
One further point: When the bearings
are driven to the bottom of their holes (you
can hear them hit home), we found the
spacer length didn’t match perfectly, and
the bearings were slightly tight. A couple
of judicious taps with a hammer on a deep
socket against one inside bearing race will
realign the bearings so they turn smoothly
and won’t cause any damage.
Wheel lacing and truing is a subject I
used to teach and is something I’ve always
enjoyed. Mark Barnes has written about
it for us (Jan. ’06) and you can read his
How-To on MCNews.com/resources
Having rims perfectly centered inside
the fork legs and swingarm is a common
concern on chat boards and a source of
complaints with some suppliers, so we
chose to true the wheels in place. With
the bike on its SW-Motech centerstand,
raised to a comfortable working height
on our Handy Mfg. pneumatic lift, this
was relatively easy. As a fork centering
tool, we cut an inch-wide piece of foam
core mat board to precisely fit between
the fork legs. This was marked at its exact
center as well as the new rim width to provide accurate guidelines. And as the rim’s
radial runout became gradually more true,
the guide could be pulled closer to the
rim, aiding in further corrections.
At the back, because the swingarm is
asymmetrical, the stock rear rim spacing
from side-to-side must be noted, and the
difference between stock rim and the new
rim’s measured so the new spacing can be
calculated. As a guide, we used another
tab of foam core material on the right side,
making truing adjustments to bring it into
alignment just shy of contact.
The lacing done, a long wrap of duct
tape, torn to fit, was rubbed tightly against
the rim to form a better seal against sudden deflation in the event of a puncture,
replacing a standard rubber rim strap.
The rims and spoke kits were purchased from ProCycle which is a DR650
specialist and a distributor for Buchannan’s. The polished sliver Excel 17" alloy
rims are 3.50" front and 4.25" rear, laced
with stainless steel spokes ($529.95 com-
plete) mounted with 120/70 and 160/60
rear tires (Note: The 160mm tire easily
fits the swingarm). To provide maximum
grip for cornering antics, a Bridgestone
BT002 Racing Street tire was fitted up
front and a BT016 triple-compound
hypersport tire at the rear. These are run
with 27/27psi front/rear with great feel
and excellent handling. We’d recommend
having these tires mounted by machine
as their low profiles make levering them
onto the rims by hand extremely difficult.
Balancing is also strongly recommended.
The DR is unique in that it allows easy
correction of the steering geometry for
the reduced axle height of the 17" wheel
vs. the stock 21" (often the source of stability problems when enduro bikes are
modified for supermoto). A second upper
mounting hole at the bottom of the rear
shock is available to lower the rear end
and restore the rake and trail.
The net result is a delightfully agile and
stable motorcycle that makes twisty
canyon roads a treat, the tighter the better.
If maximum adhesion on the road is your
desire, the supermoto DR650 can deliver.
Brakes
Above: Brake upgrades include an oversized
EBC floating rotor, which greatly improves
power with excellent feel, and a Galfer wavy
rear disc. Both are plumbed with Galfer
braided stainless steel brake lines.
Now that the bike has massive tire grip,
enhanced braking power can be fully utilized. At the back, a Galfer wavy disc was
installed. Galfer stainless steel brake lines
were next, to give the most positive
response to lever pressure. At the front, an
EBC 320mm floating rotor was installed,
which uses a gorgeous alloy carrier and
includes a neat gold-anodized caliper
relocation bracket. Note that the oversized front rotor is a snug fit inside the
17" wheel and requires the brake caliper
to be disconnected for wheel removal and
installation, a small bother.
If you have never replaced brake lines,
know that you need a tool to squeeze fluid
into the bleeders from the bottom to fill
the dry lines before you can bleed them.
Unless you have or are willing to buy a
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JUNE 2010
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Feature
Above: Control upgrades included a Phillips Motovision headlight bulb, which only changed the color of the illumination, but
next we added the Eastern Beaver headlight relay kit, which supplied full battery voltage to the bulb for a 50% improvement!
New mirrors were sourced from the KTM Super Duke which are wider to improve the rear view and also enhance the bike’s
style. PivotPegz replaced the stock footpegs for a better grip, more supportive platform and easier lever function.
tool to do this step, have someone else
install the new lines.
The results of the big front brake kit
and steel lines are impressive—very
strong and controllable stopping power
with a crisp lever feel. The 320mm EBC
brake is $239.95, the Galfer lines are
$66.95 front and $52.95 rear and its rear
discs is $125. Stock Suzuki pads are used
on both ends.
KTM Super Duke. These give a wider rear
view that’s safer without hurting lane sharing clearance. The mirrors come in two
parts, and you need both. $121.42/pair.
upholstery is firm, but seems never to get
too hard or uncomfortable. Cost: $349.95.
Carburetion
Uncorking the stock DR’s intake, fitting a K&N filter and aftermarket exhaust
makes a huge difference to power (over 6
Our efforts to find a comfortable and
hp) but causes the standard CV carb to run
attractive seat for the DR650SE were
extremely lean at lower rpm, hurting offfinally rewarded when we discovered that
idle throttle response. We tried jetting kits
Sargent Cycle was now producing one
from both Dynojet and Factory Perforspecifically for the Suzuki. With its top
11" wide (vs. just 7" on the stock saddle),
mance and after some fiddling, got both to
Lighting
it supports the boney rails of the pelvis
run well, but could not eliminate this hesTo improve the headlight’s performance
itation. Factory Pro uses a titanium
without going to a 100W bulb,
needle, which should last longer,
which can be too hot for some
and its taper isn’t nearly as rich as
housings, we first installed a
the Dynojet’s, so it will also
Phillips Motovision bulb which
improve gas mileage slightly. If
gave the same tested luminance
you’re staying with the stock carb,
but with a pinkish color. But
we recommend the Factory kit.
we got a genuine improvement
The decision was made to swap
from the Eastern Beaver H4
for a pumper carburetor, so-called
headlight relay kit (our March
because it includes an accelerator
2009 Innovation of the Month).
pump to shoot a tiny stream of gas
The kit’s relays allow full batduring acceleration and eliminate
tery power to reach the bulb,
the bog inherent when opening a
improving brightness by a measlide-throttle carb quickly.
sured 50% (at an estimated cost
Mikuni sent us the carb and we
in bulb life from 1400 hours to
then got a kit of flange adapters,
7500 hours). The kit is $54.19.
Highly recommended.
Above: Sargent Cycle’s new DR650 seat gave us a much wider jets and cables from ProCycle for
the installation ($159).
seat with softer curves. Although it feels too firm initially, it
The TM40 Mikuni is less
Controls
doesn’t induce monkey butt like the stocker. Beautifully craftexpensive than the similar FCR39
The stock pegs use a U-sec- ed, its carbon fiber weave really upgrades the bike’s style.
Keihin pumper, which can also be
tion steel channel base, and
adapted to the DR. Complete Mikuni
rather than trying to wedge them apart.
their pivot holes were already elongated,
TM40 conversion kits are available from
The Sargent seat is also beautiful, with a
so we installed PivotPegz, our May 2010
Pro Cycle for $450, or thrifty owners can
carbon fiber-look cover and uses its own
Innovation of the Month, to improve
look for used H-D Big-Twin carbs and
base, so you don’t need to send your old
comfort and ease control use while reduccustomize them with minor rejetting (a
one in for recovering. It fits both the stock
ing boot wear. We are very impressed
Harley/Mikuni HS40 is the same as the
gastank and the popular IMS 4.9 gal. plaswith these spring-loaded pivoting AusTM40).
tic version. A 1" lower version is availtralian items. Price is $149.
The advantage of the pumper carb is
To enhance the look of the DR, we
able, and the standard model (chosen) is
enormous. Throttle response is instanopted for more stylish mirrors from the
essentially the same height as stock. The
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JUNE 2010
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Seat
MOTORCYCLE CONSUMER NEWS
Above: Efforts to correct the stock carb jetting after removing the airbox cover included jet kits from both Dynojet (top) and
Factory Pro (bottom). Both gave similar results, but the Factory’s leaner needle gives better gas mileage. The decision was
made to fit a Mikuni TM40 pumper (right in center photo) which transformed response and power after dyno tuning. The TM40
also provides easy access to idle speed and mixture screws. Allen head screws replaced phillips head for easy trailside access.
taneous and acceleration is much
stronger, making a sweet difference
every moment you ride. And in the dirt,
the improvement in control is a transformation. If you have already uncorked the
DR’s intake and exhaust, this is a musthave modification.
Aftermarket Slip-On Shootout
As promised, after optimizing the carb
jetting, we compared the previously
installed FMF Q2 slip-on with the popular SuperTrapp IDS2 to see if one offered
a noticeable advantage. The SuperTrapp
has a cast aluminum cylindrical body that
features a combination of absorption
packing and the famous adjustable disc
setup for backpressure and sound adjustment but doesn’t use a larger diameter
headpipe like the FMF. We tried various
disc combinations looking for a reasonable sound level for urban use. Installed as
supplied with 10 discs, the SuperTrapp
was deafening, so we backed down in two
disc steps, eventually settling on four. Our
sound meter rated the FMF Q2 at a reasonable 93 dB (as advertised), and found the
SuperTrapp falls between 93 and 94 dB, a
touch louder.
Both pipes give the same peak power,
41.8 hp @ 6000 rpm (vs. 35.6 hp stock).
However, the FMF gives significantly better power above 3700 rpm, as much as 2 hp
@ 4750, and also a big advantage past the
hp peak (another full 2 hp at 7300 rpm).
Driveability is also improved. Although
the SuperTrapp held a slight advantage
between 2700 and 3700 rpm, the fuel curve
indicated that with the clip lower on the
needle or a different needle, the FMF
might well erase this little deficit, too.
The SuperTrapp costs less, $289 vs.
$326, but the FMF makes more hp, is 1/2lb. lighter and sounds better—FMF wins!
Building our DR650SE Supermoto has
been great fun, but we don’t want to put the
wrenches away quite yet. If we can bear
to keep it motionless in the garage for a
few weeks, cam, piston and porting mods
will comprise Phase IV, so stay tuned!
Resources
Headlight relay kit—www.easternbeaver.com
Dynojet—702-399-1423; www.dynojet.com
Factory Pro Tuning—800-869-0497l;
www.factorypro.com
FMF Racing Q2 Exhaust—310-631-4363;
www.fmfracing.com
Paul Thede’s Race Tech—951-279-6655;
www.race-tech.com
PivotPegz—Brap! Off-road LLC; 717-2857873; info@brapoffroad.com
ProCycle—Wide selection of DR650SE
parts: Exhausts, wheels, brakes, carb kits.
800-496-5516; www.procycle.us
Sargent Cycle Products—800-749-7328;
www.sargentcycle.com
SuperTrapp ISD2 Exhaust—216-265-8400;
www.supertrapp.com
41.8 hp
••
41.8 hp
FMF Q2 blue — SuperTrapp IDS2 red
Above: The FMF Q2 was compared with the SuperTrapp IDS2. Both are much lighter than the stock exhaust; the FMF is 5.0 lbs.,
the SuperTrapp is 5.5 lbs., and the standard exhaust is 13.0 lbs.—a huge weight savings that’s high and far from the CofG
where it’s very significant. Our dyno test results are on the right: The FMF has a 4 hp advantage on either side of the same power peak.
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