2020 Kawasaki KLX140L (KLX140RL) Long Term Owner Review

Review Last Updated: June 12, 2024
Vehicle Type: Off-road recreational
Evaluation Period: 4 seasons, 89 hours

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simple air-cooled motor, electric start, easy to ride, good power for the class (largest displacement), simple routine maintenance, fully adjustable rear shock, disc brakes, reliable


carburetor can be finicky to dial-in, imprecise chain adjustment marks, some rubber components rotted when we got the bike, non-O-ring chain


The model name for this bike was changed in 2021 from KLX140L to KLX140RL, but it's the same bike (no significant changes that I'm aware of).

We purchased the 2020 KLX140L new at the beginning of the 2020 riding season. We bought the bike for our kid to learn on. It was slightly on the tall side in the beginning, but now it's a bit small. Our kid likes the bike's lighter weight and lower seat compared to our CRF250F, and still thinks there is enough power, but finds the bars on the KLX140L are too low when standing up now. The low seat is an advantage in some riding conditions, but that also means our kid's knees are bent more when sitting. Our kid is now about 167 cm tall. We'll keep the bike for a while yet, but we're looking into buying another dirt bike (KLX230R S, TT-R 230, CRF250F) or a dual sport bike (XT250, KLX230S) as a step up.

The build quality seems ok (see comments below). The bike is reasonably light for the class, and it's fairly easy to ride. It's certainly not intimidating for a new rider provided they're tall enough for the seat height.

The bike has enough power for our young rider, even after four seasons. The bike handles fine on the varied trails it's been used on. It has disc brakes front and rear which provide good stopping power. I find the rear brake pedal a bit high, but that could be because my knees are bent more than a shorter rider when I ride the bike. But my kid, even early on, thought that it was a bit high too. The rear shock is fully adjustable (preload, compression and rebound damping), so you can set it up for different riders, riding style or terrain, or to compensate as the rider's skill progresses. I've found the suspension to be quite decent (no complaints). The bike comes with some engine protection: minimal plastic skid plate and metal guards extending out from the lower portion of the frame. The bike has an electric starter and a 5-speed manual transmission.

We are still on the stock tires. They've been fine for trail riding, but the bike hasn't been ridden real aggressively. The trails (mostly twin track) have varied from smooth dirt, gravel, mud, puddles, small loose rocks, embedded rock, from level ground to moderately steep hills (easy to intermediate conditions).

Maintenance, issues

Service Info

I purchased the Kawasaki service manual shortly after buying the bike, as I do for most of our bikes. The first maintenance was due at 5 hours (or 1 month) of riding time and was pretty straight forward. This service includes changing the oil and filter and checking the valve clearances as well as checking a number of other items such as fasteners, air filter, controls, etc. The KLX140L has screw type valve adjusters. The intake valve was slightly tight by 0.01 mm, but the exhaust valve was within specification. I adjusted them both to be about the midpoint of their ranges. Subsequent maintenance intervals are at 50 hours or 6 months (100 hours or 12 months for the valve clearances).

We had problems with the bike from day one. It was difficult to start (cranked over fine) and ran very poorly. The bike stumbled at low engine speed with very little power available, even when thoroughly warmed up. It was very difficult to ride the bike at slow speed. It was like the pilot jet was obstructed. The bike seemed to run ok once you got the rpms up past maybe third engine speed. We had the bike back to the dealer several times for service under warranty. The carburetor was adjusted each time and inspected once. They swapped out pilot jets (#38 to #42 to #40 and back to #42), tried shimming the needle (barely ridable afterwards), adjusted the air/fuel mixture screw and adjusted the idle speed. Sometimes it ran better at elevation, (1200 - 1500 m) and sometimes it was worse. Some of the adjustments they made resulted in the bike stalling at idle and difficulty starting the bike when hot. None of their adjustments eliminated the problems.

After the warranty period ended, I made a number of incremental adjustments to the fuel/air mixture (pilot) screw. The bike would run well at 500 m elevation with the #42 pilot jet: no bogging or hesitation when quickly opening the throttle. To run better at the higher elevations that we're normally riding at, the fuel/air mixture screw needs to be adjusted (turned out) from the setting used at 500 m (the elevation at the dealership), otherwise, the bike would hesitate (bog) when quickly opening up the throttle at low engine speed. From mid-engine speed upwards, we never experienced any noticeable fueling issues. The top-end power has been good (for the class) from the beginning, and with the fueling sorted out, the performance at lower engine speeds has been fine.

From our experiences, I would conclude that the carburetor used in this bike is very sensitive to elevation (and perhaps temperature) changes. It can be adjusted to compensate for those changes, but it is finicky. Trying to tune the carburetor at low elevation and then riding it at high elevation is not going to work well; the dealer mechanic was unable to do it even with multiple attempts and detailed information provided by us. Some of his adjustments made the bike run even worse (almost unrideable). I don't think that mechanic was very skilled (he also caused quite a bit of damage to the paint on the frame). You could try adjusting the carb and testing out the bike at the elevation you're going to ride, or you can still adjust the carb at home but tweak it for the elevation you're going to ride. Currently a #42 pilot jet is in the bike and the air/fuel mixture screw (air screw) is set to 2.0 turns out. We're running the stock main jet and needle with no shims, and mainly riding at elevations of 1200 to 1500 m. The stock pilot jet is a #38.

Other quality issues that I discovered include a cracked rubber grommet / cap on the starter motor where the wire connects, a rotted and torn rubber boot at the carburetor end of the throttle cable (the mechanic servicing the bike never reported this but should have), and one of the see-through drain tubes for the air box had a cut or crack in it. The defective parts were replaced on warranty. I also discovered a leak in the air box after washing the bike and finding a few drops of water in one of the other air box drain tubes on the clean side of the air filter (see photo). The seal between the air box and the intake to the carburetor (carburetor duct) looked questionable (the sealant was coming off), so I cleaned it up and resealed the joint with silicone sealant.

Another point of contention are the chain adjustment alignment marks: they are pretty much useless because they are so imprecise. I ended up measuring from the ends of the swingarm when adjusting the chain. It would be much easier to adjust the chain if Kawasaki had used snail-type chain adjusters like on the Honda CRF250F, Yamaha TT-R 125 and the DR200SE. Oh, and because the bike does not have an O-ring chain, I've had to adjust it frequently even though I lubricate it often.

I discovered a fuel leak from the carburetor at the end of the 2022 riding season. It looked like gas was leaking from between the float bowl and the main body of the carb. I suspected that the gasket may have been damaged when the carb was serviced multiple times at the dealership under warranty. I investigated the issue prior to riding the bike again by removing the float bowl from the carb. I was able to rotate the carb enough after removing the throttle cable and loosening the clamps in order to access the screws holding the float bowl (I didn't need to remove the carb). There was sealant holding the gasket in place (the service manual does not state to use sealant). If sealant had been used by the shop previously and had not been properly cleaned, then there may have been some old sealant preventing a good seal between the float bowl and the carb body. When I removed the screws (JIS) holding on the float bowl, I discovered that they were not very tight, and that they were mis-matched (one was a bit longer than the other and one was missing a lock washer); an original screw was probably lost when the dealer mechanic serviced the carb. So, I would say that the fuel leak was caused by improper service by the dealership (not a surprise, unfortunately). I cleaned the mating surfaces of the carb and float bowl, installed a new gasket (the old one seemed a bit hard) and tightened up the screws holding on the float bowl and then put every else back together. There has been no evidence of further fuel leaking (problem fixed).

Other than the points mentioned above, the bike has just required routine maintenance applicable to most other motorcycles. There have been no other issues.

Comparing the KLX140L (KLX140RL) to other bikes

The main competition for the Kawasaki KLX140L includes the Yamaha TT-R125LE, Suzuki DR-Z125L and the Honda CRF125FB. All four bikes have a front disc brake, an air-cooled engine, a manual transmission with clutch, a 19-inch front wheel and a 16-inch rear wheel. Another bike to include here is the Honda CRF150F, but it hasn't been available new for several years now. The listed MSRPs below are in Canadian dollars.

The Suzuki DR-Z125L (124 cc) has a carburetor, kick start (only), rear drum brake, no suspension adjustments other than rear preload, a 5-speed transmission, a curb mass of 89 kg (196 lbs) with a 4.8 l fuel tank and a 805 mm (32.0 in) seat height. It has a plastic skid plate. The warranty period in Canada is 6 months. MSRP for 2024 is $4399, up from $4199 in 2023, + fees.

The Honda CRF125FB (125 cc) has fuel injection, electric and kick start, a rear drum brake, no suspension adjustments other than rear preload, a 4-speed transmission, a curb mass of 90 kg (198 lbs) with a 3.7 l tank and a 785 mm (30.9 in) seat height. It has some engine protection. Prior to 2019, the CRF125FB had a carburetor. The warranty period in Canada is 6 months. MSRP for 2024 is $5122 (up from $5018 in 2023) which includes $523 in fees.

The Yamaha TT-R 125 (124 cc) has a carburetor, electric and kick start, a rear drum brake, fully adjustable rear shock, preload adjustable front forks, a 5-speed transmission, a curb mass of 90 kg (198 lbs) with a 6.0 l fuel tank and an 805 mm (31.7 in) seat height. It has a minimalist plastic skid plate. The warranty period in Canada is only 90 days. MSRP for 2024 is $4699 (up from $4399 in 2023) + fees.

The Kawasaki KLX140L (KLX140RL) (144 cc) has a carburetor, electric start (only), a rear disc brake, fully adjustable rear shock, a 5-speed transmission, a curb mass of 95 kg (209 lbs) with a 5.8 l fuel tank and an 800 mm (31.5 in) seat height. It has some engine protection: a small plastic skid plate and steel frame "loops". The warranty period in Canada is 6 months. MSRP For 2024 is $4549 (up from $4499 in 2023) + fees. There are two colour choices for 2024: grey or green.

We considered all four motorcycles and checked them out in person. We decided against the DR-Z125L because it was a bit too tall and was kick start only. There's nothing wrong with kick start, but we thought that having a bike with electric start would be easier for our kid to learn on. The Honda felt the smallest of the bikes, and we seriously considering buying a leftover 2018 model. We chose the KLX instead of the Honda because my kid liked it the best, we were offered a pretty good deal, it had a 5-speed transmission rather than a 4-speed, disc brakes front and rear, and a fully adjustable rear shock. On top of that, the Kawasaki has the largest motor and most likely the most torque. We felt our kid wouldn't out-grow it as quickly. The KLX had the second lowest seat height and the second largest fuel capacity. The seat height on the Yamaha seemed a little too tall at the time, and we could not get as good of a deal.

Last Words

We have had some frustration with the KLX140L getting it to run optimally at lower engine speeds. I was tempted to sell or trade it early on, but we kept it and sorted out those issues. The KLX has some redeeming qualities including making pretty good power and having decent suspension and brakes. The bike is much nicer to ride now than when it was new. So, would I recommend the bike? Yes, knowing what I know now. It might be nice to have fuel injection, but only the Honda does in this class. On the other hand, I find the throttle response a bit abrupt on my fuel-injected CRF250F and it is even worse on the CRF300L. A properly tuned carburetor works pretty darn good and provides much smoother fuel delivery than fuel injection, in my experience (I have not ridden a CRF125FB). All of these bikes are probably good choices depending on the size of the rider and how aggressive they ride. There's not much spread in the MSRPs, but dealer fees may vary greatly, so shop around.

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Service Info
2008-2021 Kawasaki KLX140 Service Info (may apply to later model years)
2020 Kawasaki KLX140 Valve Adjustment (applies to multiple KLX140 versions and model years)
2020 Kawasaki KLX140 Air Filter Service (applies to multiple KLX140 versions and model years)
2020 Kawasaki KLX140 Oil and Filter Change (applies to multiple KLX140 versions and model years)
2020 Kawasaki KLX140 Chain Adjustment (applies to multiple KLX140 versions and model years)
KLX140 Chain Adjustment Video
KLX140 Air Filter Service Video
KLX140 Oil Change Video