WHAT IS IT? Dick’s Racing progressively bores out the
stock KTM 250SX two-stroke carb from 36mm to 39mm,
installs the creative Intelajet system by Thunder Products,
cuts the slide and installs a Thunder Products Quad Flow
Wing. These mods work on the 2017 KTM and Husky two-stroke Mikuni carbs.
WHAT’S IT COST? $585.00 (complete) or $275.00
(Intelajet installed), $150.00 (taper bored), $150 (Quad Flow
Wing installed), $10.00 (cut slide).
CONTACT? www.dicksracing.com or (916) 705-3193;
Thunder Products, www.thunderproducts.com or (320) 597-2700.
WHAT STANDS OUT? Here’s a list of things that stand
out with Dick’s Racing’s 2017 KTM/Husky Mikuni carb
(1) Stock KTM carb. For over a decade KTM two-strokes came with Keihin carbs, but for 2017, KTM (and
sibling Husqvarna) switched to 38mm Mikuni TMX carbs.
This wasn’t a popular change. KTM owners had struggled
through several bad years jetting the Keihins before they
got it right at the factory. The more finicky Mikuni was
going to make all that knowledge obsolete.
( 2) Taper bore. Dick’s Racing taper-bores the 38mm
Mikuni from 38mm to 42mm at the end. Tapering the
carb’s bore allows the Mikuni to work like a 38mm carb
below one-third throttle but a big carb above that.
( 3) Intelajet. Intelajet is the two-stroke equivalent
of Kawasaki’s dual-fuel injection nozzles. As air velocity
increases, excess fuel is sucked directly from the float
bowl to a secondary emulsion tube upstream from the
main jet. At high rpm, this extra stream of atomized fuel
enters the carb as a fine mist. The amount of fuel coming
through the emulsion tube can be controlled by an air-
bleed dial that’s accessible to the rider.
( 4) Quad Flow Wing. Intake tract winglets take
tumbled air and smooth it out to reduce drag at the air’s
boundary layer. Reduced surface friction equalizes the
pressure gradient and increases air velocity. The Quad
Flow Torque Wing is unique in that it mounts on the cylinder side of the carb’s Venturi instead of the airbox side.
Why? Because it wants to straighten out the air as it exits
( 5) Slide. Raising the cutaway arch of the Mikuni slide
causes more air to flow through the carb’s venturi at low
throttle settings, creating a slightly leaner mixture at idle
and a crisper transition into the midrange
( 6) Performance. By increasing air velocity and adding a secondary fuel source, MXA was able to drop four
main jet sizes on the 38mm Mikuni. We got snappier
throttle response at half throttle and a big boost in top-end
power when the atomized fuel joined the party. The gain
in top-end power and over-rev was immediately noticeable
to every MXA test rider.
WHAT’S THE SQUAWK? Combining every carburetor
trick into one carb increases the power but also the price tag.
If you’re looking for the last bit of extra
DICK’S RACING KTM 250SX INTELAJET MIKUNI MODS
oomph from your 2017 250SX or TC250 two-
stroke, this is where you’ll find it.
MXA TEAM TESTED