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THEY’RE BACK! TWO - STROKES DOMINATE OFF - ROAD RACING
CCC
02977
OCTOBER 2011
DIRT BIKE
•
OCTOBER 2011
JOSH
STRANG
•
www.dirtbikemagazine.com
PRACTICE
MX AND
WIN
OFF-ROAD
HUGE
TEST
AND HOP-UP
SPECIAL
TIPS AND TRICKS
• FACTORY MECHANIC SETUP TIPS
• RIDING TACTICS FROM THE PROS
DB_OCT 11_Cover.indd 1
MORE
PERFORMANCE
LESS
MONEY
-
PUNCHED OUT KX265 & WR269
KTM 450SXF
VERY DANGEROUS!
HUSKY 310 DUAL- SPORT
SHOCKINGLY GOOD
$4.99
Att’n retailer:
Please display
until Oct 13
8/1/11 5:00:53 PM
THUMPER p90-92:Layout 1
8/3/11
2:29 PM
Page 2
OFF-ROAD TEST
THUMPITYTHU MP THUM P
Adding displacement to the WR250
n stock trim, the WR250 is a quiet and stealthy little
trail machine with smooth, electric-like power. It’s a
blast to ride tight singletrack, but out in the wide-open
spaces, it leaves a little to be desired. Luckily, the
WR250 has a lot of untapped potential. Simply going
with a quality aftermarket exhaust adds ponies, but there
is another way to boost power, and that is by adding displacement. The Cylinder Works kit is a drop-in-and-go
deal, bumping up the displacement to 269cc. The kit
comes with the Cylinder Works 3mm over bore cylinder,
Vertex piston and Cometic gaskets—all for $599.99. The
kit is lower compression than many big-bore kits, so it
runs just fine on 91-octane pump gas.
I
DeCal Works did up the custom graphics with Dirt Bike
logos. Renthal bars, grips, hand shields, O-ring chain
and sprockets handle their respective duties. Works
Connection scattered some cool billet goodies on the
WR269. We ran a full FMF system with Powerbomb header
($279.99) and Powercore 4 muffler with spark arrestor ($299.99).
90 www.dirtbikemagazine.com
We installed the kit in a WR, and to further help the kit
add more boost, Hot Cams Stage 1 cams were bolted
into a Thumper Racing-massaged head. The cams use
stock valve springs and aren’t hard on the valve train,
helping keep the reliability strong. Thumper Racing, after
installing all the hard parts, removed some stock stuff,
like the emission pump and other emission-related
accessories, turning the bike into a closed-course or private-property machine. In hindsight, we would have left
the emissions equipment on so we could use the bike on
public land. The gray wire mod was performed, which
means clipping the gray wire to let the bike rev higher.
The final step was to add a Dyno Jet kit.
P
THUMPER p90-92:Layout 1
8/2/11
3:19 PM
Page 3
Kyle Redmond hammers the WR269
around his practice
track, kicking sand in
the faces of those
aboard a stock WR250.
OCTOBER 2011 / DIRT BIKE 91
THUMPER p90-92:Layout 1
8/2/11
3:19 PM
Page 4
OFF-ROAD TEST
HIT IT HARD
Schmidt Performance went with a
basic revalve on the forks and shock
with stock springs. They added a little
more low-speed dampening on the
forks to help keep them up in the stroke
to fight dive. They also added more
high-speed bottoming resistance for big
G-outs. The shock attention went to
smoothing out the transition from low to
mid-speed dampening to help on
square-edge chop, along with adding
more high-speed bottoming resistance.
Fork revalve with oil runs $200 and
shock revalve with oil runs $200.
THUNDERING THROUGH
THE WOODS
From the moment we hit the start
button, the idea of the stock WR250
The complete Cylinder Works kit runs
was washed away with the throaty
$599.95, while each Hot Cams sells for
sound pulsing from the FMF exhaust
$199.99. The Yamaha runs an intake and
system. The redone engine pulled hard- exhaust cam. The Cylinder Works cylinder looks stock, so you can trick your
er off bottom, ripped through the mid
riding buddies.
and screamed like an MX 250F up near
the rev limiter. Comparing our big bore to a stock WR250 wasn’t really fair as it
morphed into a track racer rather than a healthy—albeit legal—trail machine;
although in hindsight we would have opted for more muscle, but never at the
expense of trail legality. We liked the suspension work; it retained good smallbump absorption, but stayed stable and was much better when slamming across
creeks and smashing through rolling whoops. If you have a stock WR250 and are
looking for a stunning shock to the fluffy powerband, the Cylinder Works kit is a
smoking deal, especially if you are due for a piston anyway. ❏
92 www.dirtbikemagazine.com
Having a little extra power is a treat.
Kyle using a tree as a pivot.
C O NT A C T S
Cylinder Works....www.cylinder-works.com
(515) 251-4070
Vertex Pistons ......www.vertexpistons.com
(515) 270-2302
Cometic Gasket ............www.cometic.com
(800) 752-9850
Hot Cams ................www.hotcamsinc.com
(515) 402-8200
FMF Racing ................www.fmfracing.com
(310) 631-4363
Thumper Racing ..www.thumperracing.net
(661) 424-1800
Works Connection ....................www.works
connection.com; (800) 895-8292
Renthal ............................www.renthal.com
(877) 736-8425
Uni ................................ www.unifilter.com
(714) 535-6933
DeCal Works ................www.decalmx.com
(815) 784-4000
Dunlop Tire....www.dunlopmotorcycle.com
(800) 845-8378
Moto Seat ..................www.motoseat.com
(951) 258-5229
Bel-Ray ............................www.belray.com
(732) 378-4080
Schmidt Performance ..........www.schmidt
performance.com; (951) 251-5133