KTM Motorcycle tests
WHAT IS IT?
Dick’s Racing progressively bores out the stock KTM 250SX two-stroke carb from 36mm to 39mm and installs the creative Intelajet system. It fits on all KTM two-stroke carbs from 2004 to 2012.
WHAT’S IT COST?
$425.00 (carb bored progressively from 36mm to 39mm with Intelajet installed); $30.00 (Intelajet mounting kit); $40.00 (taper-bore carb ends).
www.dicksracing.com or (916) 722-2373.
WHAT STANDS OUT?
Here’s a list of things that stand out with Dick’s Racing 36mm to 39mm carb mod.
(1) Stock KTM carb
. Believe it or not, KTM mounts small 36mm Keihin PWK carbs on their 250cc and 300cc two-strokes. Most two-strokes come with 38mm or larger carbs.
(2) Dick’s Racing carb.
Dick Wilk taper-bores the stock KTM carb so that it flows from 36mm to 39mm; he can also taper-bore the ends for even more power. Tapering the carb’s bore makes the Keihin PWK work like a 36mm carb below one-third throttle but a big carb above that.
What is Intelajet? It is the two-stroke equivalent of the dual fuel-injection nozzles on the 2012 Kawasaki KX250F. The Keihin carb functions normally below two-thirds throttle, but as air velocity increases, excess fuel is sprayed out of the Intelajet’s emulsion tube upstream from the main jet. It has the feel of a supercharger. The Intelajet doesn’t dump raw fuel into the carb as much as it sprays a fine mist into the air stream to enhance fuel burn at high rpm. The amount of fuel coming through the emulsion tube is controlled by an air-bleed dial, which is accessible to the rider.
The only jetting change that we made to our preferred 2012 KTM 250SX brass was to replace our 160 mainjet with a smaller 152, because the Intelajet emulsion tube spray makes up for any loss in high-rpm fuel.
. Awesome! Incredible! Worth the money! Amazing! Fantastic! Unbelievable! Pick the adjective that you like best. The gain in top-end power and overrev was immediately noticeable to every MXA test rider. It has no effect on power below two-thirds throttle, but once the mist kicks in, the KTM 250SX feels like it has a jet pack attached to it.
WHAT’S THE SQUAWK?
We had to fiddle with the needle clip and air screw to keep the midrange tuned to the high-rpm overdrive, but it was not a big deal.
In three words: we love it.