2023 KTM 150XC-W TWO-STROKE: FULL TEST

Frankly, there’s no army of high-tech 150cc dirt bikes invading the off-road/enduro domain. This is a unique class of machines, and they target pilots who are…sized right for the job. The 2023 KTM 150 XC-W is a high-end, totally sophisticated, offroad machine that under the proper tutelage- is an absolute weapon. This machine was introduced in its fuel-injected form back in 2020 and has benefited from focused updates in suspension versatility, along with performance enhancements via ECU settings. But, it’s the whole package that makes this machine almost effortless to manage in a hostile environment. It’s light, nimble and powerful enough, and it feels like a mountain bike in nasty terrain. Let’s have a look.

BEHIND THE CURTAIN

KTM may have dropped the TPI from the XC-W line name (all the two-strokes are TPI), but the cylinder retains the 58mm bore, and for the fuel-injected application, the cylinder features two domes that hold the fuel injectors, supplying fuel to the rear transfer ports. The downstream injection of the fuel mixes with the upstreaming air. This is the same system used on all the 150cc, 250cc and 300cc XC-W TPI models. A small tube located in the rear of the cylinder is connected with an intake pressure sensor. This sensor supplies pressure data to the control unit. Back in 2020, the upper contour of the exhaust port was machined to ensure more accurate port timing, and the exhaust system was designed using 3-D stamping technology. This, along with a new muffler with a hi-flow core, paved the way for the off-road holy grail—a broad powerband in a 150cc dirt bike.

Naturally, the 150XC-W uses a wide-ratio, 6-speed gearbox designed by Pankl Racing Systems for KTM. The clutch is hydraulic, powered by Brembo, and uses the very effective KTM DS (diaphragm steel) system that improves engagement via a Belleville washer. Unlike the six separate coil springs used on most bikes, the largediameter Belleville washer applies pressure to the clutch pack evenly around its circumference. The new DS clutch is lighter and doesn’t have the cush hub-style rubber bumpers that the DDS clutch has.

It has electric start, retains a kickstarter, and uses oil injection rather than traditional pre-mix. The oil pump delivers the juice to the throttle body where it mixes with incoming air. Using engine speed and a throttle-position sensor, the engine’s management of the oil pump sends the precise amount of oil to the piston and crankshaft. It works out to an average ratio of 80:1 (slower speeds require far less oil), and the tank totes enough lube for four to five tanks of gas.

Again, like all KTMs, it uses a chromoly steel frame. KTM redesigned certain frame sections with greater lateral, longitudinal and torsional stiffness a few years back, targeting rider comfort and overall stability. Both suspension ends are handled by WP. The fork is a 48mm WP Xplor and uses a split-fork design. Basically, this means that although it does have springs in both fork legs, the legs have separate damping functions. The left handles compression damping, and the right takes care of rebound damping. Both can be adjusted at the top of each fork and have a total of 30 clicker positions each.

The swingarm is a one-piece design using a gravity die-cast process for strength and low weight. The rear WP Xplor shock is linkless, which saves weight, and is celebrated for its ability to absorb off-road hack, ruts, roots, and rocks.

LET’S GET MOTIVATED!

Our top off-road/hard enduro/trials tester here is Ryan Koch. Ryan’s compact size (5-foot-7, 135 pounds) makes him the perfect test mule for the 150. Here’s his feedback on the KTM 150XC-W.

Power:

“The engine is one of the biggest surprises yet. Featuring TPI fuel injection and oil injection, the 150XCW has an ultra-crisp and beyondclean throttle response with a top-end pull that yanks to the moon. Bottomend power is quite good—not as strong as the 200s of the past, but the bike will carry second and third gear in most trail situations. Where it falls flat is the midrange. You’re forced to pour in some more clutch work to keep the bike in the meat of the power. Once past the midrange, the 150 screams up top and allows you to climb some very hefty hills with proper input. The 6-speed transmission offers excellent spacing, with first being a granny gear for trials-bike-like situations out on the trail. Sixth doesn’t feel as tall or spaced out as on the machine’s big brothers, but it will allow you to cruise along at a good clip. The famous KTM DS clutch makes for nearly fadefree operation. On extreme hill-climbs, we felt a touch of fading near the top, but nothing concerning. You are just much more reliant on the clutch to keep the machine up on the pipe to clean hills, resulting in light fade if the clutch is overly abused.”

Suspension:

“Being an XC-W model automatically means the bike is equipped with PDS and no linkage. For slow-speed enduro work, this chassis with PDS is among my favorites. The bike will track ultra straight, yet has a very responsive and quick-turning nature. Much of the stability comes from the XPLOR fork and shock. This fork is strong in most all off-road conditions, but really shines on slower-speed and rough trails. There is zero deflection in the rocks and trail hack. Unlike in years past, the XPLOR fork retains much more hold-up when the speeds pick up, making the 150XC-W quite stable at speed. The shock pairs very well with the fork, providing a very balanced platform overall.”

Bits and pieces:

“Controls on the 150XC-W are Brembo hydraulics all around. Top marks go to the braking power and smoothness of operation even on the steepest terrain. Never once did we experience fading or any change in pressure in the brakes. The Brembo clutch master cylinder on the 150 has one of the lightest pulls we’ve felt. Upon inspection, we found it comes with a #9 master-cylinder piston as opposed to the #10 that the larger bikes come with, resulting in the lighter pull. We love that the bike comes stock with handguards and a fairly sano skid plate. Having a headlight is usually a must for our adventures, and the 150 headlight passes inspection. It will get you home after dark and make night riding manageable.

 

 

“Keeping the 150XC-W hooked up are a Dunlop AT81 out back with a Dunlop MX33 up front. Love the front, and the rear is decent in hardpack and rocks and roots. Neken bars offer a comfortable bend, and the cast triple clamps offer a load of handlebar positions to dial in the ergos. I’m not a fan of the brake-pedal tip; it’s far too narrow and pushed in too far, making it easy to miss. The seat foam is medium density, not too hard or soft, with a gripper cover that isn’t abrasive. Air-filter access remains a tool-free job, making it painless to maintain your machine.”

Ryan’s bottom line:

“I’m a bit disappointed that an off-road machine like this doesn’t come with a spark arrestor. For the price and considering the places customers will ride this bike, you would think it would be equipped with one. I’d like to see a bit more midrange power and will try some mods to see if that’s attainable. The light weight is the selling point of this machine. Smaller riders will be able to flick this small bore around much easier than a 250 or 300, resulting in less fatigue at the end of the day. I’m pumped the bike comes with a backup kick-starter and think all machines should still have this option. The oil injection is amazing, allowing for much more oil efficiency and cleaner burning. The best advancement in technology is the ability to run spot-on and clean at any elevation, thanks to the TPI fuel injection. No jetting necessary results in perfect fueling and more ride time.

“Overall, the KTM 150XC-W has to be one of the best off-road bikes of the year. The light weight is addictive, making the pilot giggle on any trail that is flowy and downhill, since the bike has a mountain-bike-like personality.”