2021 Kawasaki KLX300 and KLX300SM

Some riders believe an adventure bike requires gobs of horsepower and torque, which excels on tarmac, but comes at the expense of weight, off-road agility and greenbacks. Others prefer a lighter, nimbler, more affordable and off-road friendly package, which is what Kawasaki’s KLX and KLR series has always presented. After a decade and a half of success with the virtually unchanged KLX250, team green has finally updated it, ever so slightly, with features that likely should have been included from the start.

Rather than reinventing the platform, or adding tons of heavy and complex technology, only a few subtle changes were made. However, these updates make a rather large impact, and this already great bike is now even better. Additionally, Kawasaki added a supermoto on the same platform to the lineup — a gauntlet thrown directly at Suzuki’s long-in-the-tooth DR-Z400SM.

The differences between the two KLX models include primarily gearing, suspension and tires. We’ll focus on the more off-road capable, dual-sport KLX300 and mention any notable changes with the street-oriented KLX300SM.

Kevin Wing

The simple KLX enhancement recipe included adding fuel injection and bumping the displacement from 249cc to 292cc, via a 6mm increase in bore (from 72mm to 78mm). The 61.2mm stroke was left unchanged. What results is more power from the same liquid-cooled, four-stroke single. Four-valve DOHC profiles were sourced from the KLX300R MX model, which was already dialed in for the additional displacement. The flat-top piston and pentroof chamber deliver a 11.1:1 compression ratio, up from 11.0:1 on the KLX250. In practice, this equates to smooth and consistent power delivery from start all the way to the 10,000 rpm rev limiter.

The old carbureted KLX250 was a fair-weather friend, which did not start well when cold, or run well at low rpm. It felt fuel starved. Adding fuel injection solved these nagging fueling problems and the extra power helps performance everywhere. We started our ride through California’s Sierra Nevada foothills on a brisk 45-degree morning, well above sea level. A quick press of the electric start, and the bike fires up and idles comfortably, even in cold temps at higher elevations. Electric start and fuel injection should be reason enough for any aging thumper rider (bike or body) to upgrade to a newer model, especially those who are still kick-starting!

The engine features a gear-driven balancer, which seems a bit pointless on a small-bore thumper, especially considering it must be wound into the top half of the powerband to make a reasonable amount of power. Regardless, there is heavy and continuous vibration in the bars, seat and pegs anytime it is pinned over 7,000 rpm, which is most of the time. For anyone who loves singles, or “feeling” the bike, this will come as no surprise, and vibration should be considered part of the package.

The throttle is cable actuated and response was smooth overall, but off-to-on throttle was sometimes a tad hesitant. This was most noticeable on the SM, when aggressively trail braking into, then accelerating through corners. A delay in the throttle hit at full lean destabilized the chassis, but the timing was manageable with practice. Club racers considering this bike may want to dial throttle transitions in a bit tighter after purchase, for more immediate response.

A six-speed transmission offers a 14/40 drive ratio (14/37 ratio on the SM), which has billy-goat grunt down low, and will happily send up a dirt vert. Steep climbing, roosting and bobbing through ruts and deep-water crossings were all easily accomplished with zero complaint from the bike. However, stacking 200 pounds of meat, wrapped in abrasion resistant materials, on top of a 300-ish-pound bike, topped out at about 60mph when trying to climb steep freeways at speed.

Lighter weight and flatter-highway riders will fare better, as the top speed should be north of 70mph without the resistance of physics. This is one place the supermoto shines, as the higher gearing allows for better acceleration and higher top speed, which was a clear improvement at freeway speeds, hitting well into the 80s.

Shifting was generally smooth in both directions, and can easily be done sans clutch, when necessary. Finding neutral was also easy, sometimes unintentionally. However, downshifting into first was a bit clunky, even in motion. Overall, shifting was uneventful and as good as expected for the nature of the bike. Anyone who rides the KLX300 above its remarkably competent capability, is certainly a skilled enough rider to handle any limitations of its mechanical-natured technology.

The 43mm inverted cartridge fork (USD) offers 16-way adjustable compression damping, which means there should be a setting for almost any size rider. We suggest adding a few clicks to firm up the stock setting for larger riders. The gas-charged Uni-Trak shock out back features preload, 20-way compression and 30-way rebound damping. The level of adjustability is better than most bikes, especially those on the entry level of price and performance. As such, both models can be enjoyed by almost any rider, of any skill level, in any conditions, straight out of the crate.

The dual-sport model features 10-inches of travel up front and 9.1-inches in the rear. That would be remarkable enough, if the supermoto didn’t feature 9.1-inches and 8.1-inches of travel, respectively. Either of these bikes can take a decent hit without bottoming out, and have enough ground clearance to make it through tough terrain.

The same box-and-tube, high-tensile steel perimeter frame from the KLX250 is carried over to the new model. A lightweight, rigid aluminum swingarm helps reduce unsprung weight at the rear. The KLX300 features a 56.7-inch wheelbase and an ample 10.8-inches of ground clearance. When combined with a 26.7-degree rake and 4.2-inches of trail, it makes for a stable and planted feeling, no matter what surface is being ridden. However, the handlebars on the dual sport were too low and far back for comfortable stand-up riding with a six-foot frame. Shorter riders may fair better, but taller bars or bar risers are suggested for any serious off-road use.

The KLX300SM has a slightly shorter 56.5-inch wheelbase and 9.3-inches of clearance, plus shorter 25.0-degree rake and 2.8-inch trail. When paired with 30mm narrower handlebars, placed closer to the rider, the steering felt more finicky. That is not to say the SM was ever unstable, only that it felt less stable when pressed toward its limits. Adding a simple mechanical steering damper would probably pay confidence dividends for anyone doing aggressive riding on the supermoto, and it almost seemed like an oversight that one wasn’t included.

The dual-sport features a traditional, off-road style, spoked 21-inch wheel up front and 18-inch in the rear. The stock Dunlop D605 are excellent 50/50 tires, riding smooth on the highway, and providing great traction in everything but the softest sand and mud. There would be little reason to swap any of this kit out for more than marginal gains.

The SM runs 17-inch both front and rear, and while shod stock with grippy, performance, IRC brand street tires, it still offers 9.3-inches of clearance. We contemplated throwing 80/20 tires at the SM, to make it more dual-sporty, and nearly as off-road capable as its dirty sister.

Both bikes feature a single-piston caliper gripping a 240mm rear disc brake, which engages aggressively. The dual-sport has a 250mm front disc with twin-piston Nissin caliper, which was also quite responsive, requiring a gentle application when applied off-road, lest the front end wash out. The SM jumps that up to a 300mm semi-floating front disc, which provides excellent feedback and ample stopping power, for more aggressive street riding. Overall, the brake kit on both bikes is more than up to the task, and with a little saddle time will become second nature. It is nice to see small street legal bikes, especially those designed for off-road use, not mandating heavy, expensive, and mostly unnecessary ABS.

Kevin Wing

The narrow, but thick, seat is densely packed and quite uncomfortable on the tailbone on longer rides. There are minuscule passenger accoutrements, but it is unlikely anyone is going to ride either of these bikes two-up. The KLX300 seat is 35.2 inches off the deck, but does not feel as tall when the preload is compressed once mounted. Due to the light weight and narrow frame, it is quite easy to get at least one foot flat. The SM sits a bit lower at 33.9 inches unladen, which is quite manageable for even the shortest of inseam. In fact, the combined narrow width, low weight and seat height make the KLX300SM a great choice for shorter riders.

The digital LCD cluster is a carryover from the former model, featuring an easy-to-read numeric speedometer and bar-style tachometer, as well as a clock and dual trip meters. It glows amber at night on the dual-sport and blue on the supermoto, but was easily visible in direct sunlight, as well. All other info is displayed via indicator lamps: engine, low fuel, oil temperature, high beam, neutral and turn signals. It may be basic, but it is completely functional.

The mirrors on the dual-sport are round, and effective, however the more stylish and pointy mirrors on the SM are heavier and suffer ample movement from both vibration and wind blast, making them far less usable. Footpegs on the dual-sport are grippy metal cleats, replaced by rubber-topped pedestals on the supermoto. Lighting is surprisingly not LED, and leaving the key on will drain the small battery in short order, leading to our discovery that these bikes are also easy to bump-start. Fortunately, the alternator was up to the task and a short jaunt recharged the battery enough to use the starter again.

David Hilgendorf

The $200 upcharge for the KLX300 Fragment Camo colorway features a blacked-out body, frame, fork and rims, versus the silver parts on all other models. It also limits the amount of green, if that’s not your color of choice. In addition to Kawasaki’s signature Lime Green, the KLX300SM also comes in (wait, what?) Suzuki or Yamaha Blue, though Kawasaki named its azure something entirely less interesting, or competitive.

The KLX300 dual-sport lists for only $100 more than the off-road-only KLX300R, adding about 20-pounds of street-legal kit, and subtracting roughly an inch of suspension travel, ground clearance and seat height — a great trade-off, in our eyes. The KLX300SM adds another $400 to the MSRP, and yet another inch lower measurement in all the same areas, plus smaller wheel diameter. We recommend picking the model most in line with rider height and the type of terrain to be conquered, as they are all essentially the same bike underneath.

It is puzzling that the only OEM accessory of note was a rear fender rack. However, since all KLX 250 and 300 models share common underpinnings, it shouldn’t be hard to find aftermarket accessories that fit, including soft bags, hand guards, skid plates and other adventure oriented farkles.

Though these motorcycles are already “available” at dealers, Kawasaki informed us that demand is outpacing supply, and though unmentioned, this is likely exacerbated by worldwide supply chain issues. Inventory is frequently sold before the dealer takes delivery. Welcome to the new world.

As delivered, the KLX300 and KLX300SM pack ample utility and smart upgrades into an affordable and already proven package. Either model would make a great first, second, or only bike, regardless of rider experience. Or buy both and have fun and capable street and dirt bikes for less than most other motorcycles. That is the definition of value.

2021 KLX300 $5,599 Lime Green, $5,799 Fragment Camo
2021 KLX300SM $5,999 Lime Green or Oriental Blue


Published by David Hilgendorf

Nomadic Guide, Vivid Storyteller, Brand Champion — Alfresco.

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