WHAT IS IT? The Triga iBoost2 is a sleeve, butterfly
valve and butterfly shaft that allows you to reduce the
size of your throttle body’s venturi tube.
WHAT’S IT COST? $349.95 (throttle body kit), $119.95
CONTACT? www.procircuit.com or (951) 738-8050.
WHAT STANDS OUT? Here’s a list of things that
stand out with the Triga iBoost2 throttle body reducer
(1) The kit. The iBoost2 kit includes a blue reducer
tube, two butterfly valves (one for the stock bore and
one for the smaller tube), a new butterfly shaft (that is
thinner and less obstructive), two screws (to attach the
butterfly to the shaft) and an instruction sheet. It is
available for all modern motocross brands.
( 2) Theory. Just as you could change the size of your
old-school Mikuni carb in the two-stroke days, you can
change the bore size of your bike’s throttle body with
the Triga iBoost2. The manufacturers do change the bore
size on their bikes occasionally. KTM went from a 42mm
throttle body to a 44mm bore in 2013. Triga’s tubular
insert reduces the overall flow area and pressure drop,
which increases fuel velocity through the intake port. As
a rule of thumb, smaller bores increase throttle response
and low-to-mid power, while larger bores decrease
low-end throttle response and improve mid-to-top power.
( 3) Sizing. MXA chose to install the Triga iBoost2 in
a 2014 KTM 350SXF for two reasons. First, the KTM is a
high-rpm engine that produces its peak power at 12,800
rpm. We wanted more bottom and mid to make the bike
feel like a small 450 instead of a big 250. Second, KTM’s
factory bikes run 42mm throttle bodies instead of the
stock 44mm unit. We believed that going smaller would
make the bike easier to ride in the lower rpm ranges.
( 4) Performance. On the dyno, the Triga iBoost2,
which downsized the throttle body bore to 41.5mm,
didn’t show any significant gains in horsepower, nor any
significant losses. But on the track, it was quite differ-
ent. It was torquier at low rpm, more manageable in the
middle and felt slower. Half of the MXA test riders loved
the new feel, while the rest preferred the stock high rpm
powerband. Novices and Vets thought it was easier to
ride, while Pros didn’t want anything to do with it.
Triga is all about the feel, not about the numbers.
WHAT’S THE SQUAWK? Three quibbles: (1) We had
trouble using the Triga tuning tool and opted to reset
the TPS to KTM specs with an ohmmeter. ( 2) You will
need reasonable mechanical skills to tear your throttle
body apart and reset the TPS. If you don’t have those
skills, you should have a qualified mechanic do the work.
( 3) At $350 (plus labor if you can’t do it yourself), this is
a pricey mod for a modest improvement.
Downsizing the throttle body increased fuel
TRIGA IBOOST2 THROTTLE BODY INSERT
velocity—which pays dividends in the
low-to-mid range. Our KTM 350SXF didn’t
lose any horsepower, but it felt like a mellow
Open bike instead of a hot-rod 250.
MXA TEAM TESTED