Kawasaki 125 Dirt Bike (KX) Specs and Review

On the time of its launch, the Kawasaki 125 Grime Bike was thought of a formidable contender of the 125-class. Its 1984 redesign marked the start of the KX™ lineup, re-establishing credibility – a superb comeback for the Japanese producer after experiencing a low in gross sales within the ’70s and early ’80s. A strong filth bike with a variety of promise, the KX 125 positioned Kawasaki again on the map of MX racing.

The Kawasaki 125 Grime Bike was a 124-cc off-road bike produced by Kawasaki from 1974 to 2009. This seemingly easy, enduro-style machine featured an all-new design that obtained the ball rolling for higher-displacement bikes that ultimately went on to win Baja championships.

Ingenuity was at all times a serious promoting level for Kawasaki. And but, it took nearly a decade for Workforce Inexperienced to comprehend the identical for the KX 125.

Fortunately, issues weren’t but too late, and the bike’s main overhaul in 1984 put it in favor of customers and lovers alike for one more 25 years.

Learn on, and uncover this and an entire lot extra in regards to the Kawasaki KX 125 on this article.

Green Dirt Bike on Dirt Track

In regards to the Kawasaki KX 125

The Kawasaki Grime Bike 125 is a renaissance of the 1983 Quacker, identified for its huge horsepower however severely criticized for its design deficiencies. Throughout its development, the Japanese producer removed the unwieldy chassis, harsh forks, flimsy metallic, and unimpressive styling of its predecessor, protecting solely two sturdy factors – the entrance disc brake and the highly effective motor. The KX 125 was then redesigned after the Works Machine of Jeff Ward (retired Kawasaki motorsports champ and IndyCar racer).

A Notch Greater

Key enhancements of the Kawasaki 125 2Stroke are mirrored in its framework, motor, transmission, and general reliability. The chassis was configured with a shorter wheelbase and a steeper head angle, making for sooner steering enter response and improved dealing with when climbing.

Bigger tubing in essential areas and elevated gusseting on the swingarm pivot made the brand new body lighter however extra sturdy. Workforce Inexperienced engineers strengthened the crankcases and elevated the floor mating space to resolve points with air leaks.

Different updates included wider-toothed gears, new friction plates with embedded radial grooves for the clutch, inside porting, and all-new enlargement chamber and ignition. Enhancements made to the bike’s cooling system had been significantly notable.

In comparison with the previous-year model, the 1984 KX obtained an extended single-sided radiator and enlarged water passages, addressing overheating points and leading to a 29% cooling capability improve.

On account of these modifications, the Kawasaki Grime Bike 125 felt extra like a 150-cc machine and turned from an MX bench hotter to a powerhouse. It pulled earlier on the tracks and did so with extra authority than its same-displacement counterparts. The brand new motor additionally made the bike appropriate for nouveau riders and never simply professionals.

That One Handicap

Whereas the KX 125 was thought of greatest in energy output and placement, its suspension system nonetheless screamed enchancment. Sadly, tweaks performed on the bike’s suspension parts weren’t sufficient. The marginally stiffer springs nonetheless felt underdamped for intermediate to professional drivers.

Resulting from giant jumps nonetheless ending in crash landings and complaints about harsh spikes within the mid-stroke, the Kawasaki KX 125 was thought of as having the worst front-end efficiency of all 125-class bikes in 1984.

This isn’t to say that the insufficient suspension system was its solely long-standing difficulty. Entrance disc brakes had been nonetheless vulnerable to leaks and in want of fixed bleeding. Plastics continued to have a tendency to interrupt, particularly for hard-ridden or competitors wheelers – amongst different issues.

However regardless of falling quick on these facets, the Kawasaki 125 Grime Bike was, nonetheless, a strong and dependable machine. Its setbacks weren’t impactful sufficient to derail the bike’s rise to fame because the “Ruler of the Roost.”

Kawasaki 125 Grime Bike Specs & Options


A liquid-cooled, 2-stroke single-cylinder energy mill with high-tech carbon fiber reed valves powers the Kawasaki 125 Grime Bike. It has a bore-stroke ratio of 54 × 54.5 mm (2.13 × 2.15 inches). Engine displacement is 124 cm³ (7.6 cu in³), whereas the compression ratio is 10.6:1 (low pace)/8.1:1 (excessive pace). A 34-mm Mikuni carburetor with a flat backside R-slide handles the air-fuel combination. For later-year fashions, carb measurement was upgraded to both a Keihin PWK36S or a Mikuni TMX38X.

The above engine configuration lends to a Kawasaki 125 Grime Bike prime pace of 55 – 60 mph (88 – 96 km/h), 26.5 Nm (2.7 kgf-m, 19.5 ft-lb) @ 2,700 RPM most torque, and 40.49 hp (29.6 kW) horsepower. Later-year variations outfitted with the 38-mm Mikuni carb rendered a prime pace of 75 mph (120.7 km/h), 41.04 hp (30.6 kW) @ 11,500 RPM horsepower, and a most torque of 27 Nm (2.75 kgf-m, 19.92 ft-lb) @ 10,500 RPM.

Gasoline & Lubrication

Gasoline tank capability is 8.2 L (2.2 US gal) of unleaded gasoline with a minimal score of PON 87/RON 91. Due to the KX 125’s engine configuration, the bike presents a good gasoline financial system of 60 mpg (3.92 L/100 km). The producer recommends gasoline variants containing < 5% MTBE (Methyl Tertiary Butyl Ether), < 10% ethanol, or < 5% methanol. However within the occasion engine knocking or pinging happen, switching gasoline manufacturers is suggested to forestall extreme engine harm.

Moreover, it requires 0.7 L (0.74 US quart) of Ok-Tech 2-stroke oil or its equal. The really useful oil viscosity is SAE 10W-40 with a minimal API grade of SJ assembly JASO T903 MA, MA1, MA2 requirements. Relying on ambient temperature, it’s possible you’ll go for SAE 10W-30, 10W-50, 20W-40, or 20W-50. All the time test the handbook when utilizing different lubrication on the KX 125. In any other case, it’s possible you’ll encounter poor working or lack of energy at excessive speeds if the viscosity grade is just too excessive.

Green 2005 Kawasaki KX125 Dirt Bike


A handbook (wide-ratio) 6-speed fixed mesh return system (left-foot operated) and a moist, multi-disc clutch meeting ship energy to the wheels. A 520 O-ring chain (with 112 hyperlinks + joint) handles wheel spin. The Kawasaki 125 Grime Bike’s wide-ratio transmission is answerable for its capacity to drag forward of the competitors on racetracks and produce huge energy with fewer revs, placing it on par with 250-cc wheelers. For ’92-’93 fashions, entrance and rear sprockets modified from 13/51T to 12/49T (4.08), additional enhancing acceleration.

For reference, the inventory gear ratios are beneath:

Main Discount Ratio 3.200 (64/20)
Ultimate Discount Ratio 3.923 (51/13)
Transmission Gear Ratio (1st) 2.384 (31/13)
Transmission Gear Ratio (2nd) 1.857 (26/14)
Transmission Gear Ratio (3rd) 1.529 (26/17)
Transmission Gear Ratio (4th) 1.294 (22/17)
Transmission Gear Ratio (5th) 1.125 (27/24)
Transmission Gear Ratio (6th) 1.000 (25/25)
Total Drive Ratio 12.553 @ High gear


The 125-cc Kawasaki KX has an digital CDI (Capacitor Discharge Ignition) and a major kick-start system waking it up. The car’s general charging system is a flywheel magneto, which additionally powers up digital equipment. Ignition timing is 13° BTDC @ 9,710 RPM (preliminary “F” mark).

All fashions have a 130-CCA 12V (6 Ah)/10 HR YTZ7 battery (view on Amazon) with dimensions of 113 x 70 x 105 mm (4.44 x 2.74 x 4.12 inches – L x W x H). They require an NGK BR9EIX spark plug with a 0.7 – 0.8 mm (0.028 – 0.031 inch) hole and tightening torque of 27 Nm (2.8 kgf-m, 20 lb-ft) – aside from the ’97 mannequin, which has an NGK BR9EVX plug. European releases have both an NGK R6918B-9 or NGK BR9ECMVX plug kind.

Tires & Brake

The entrance and rear aluminum wheels use Dunlop® tires. You may swap out the entrance tires for Maxxis M7304D Maxxcross Desert IT Tires (view on Amazon). Equally, rear tires may be modified to Dunlop Geomax MX33 Tires (view on Amazon) – good for soft-to-intermediate terrain.

Really helpful tire strain is reliant on monitor situations – 80 kPa (0.8 kgf/cm², 11 psi) for muddy, sandy, or slick terrains and 100 kPa (1.0 kgf/cm², 14 psi) for pebble-laden or hardpack surfaces. The correct amount of strain will both improve the tread floor on the bottom or assist forestall punctures or tire harm. Lastly, a 220-mm (8.7-inch) entrance disc with dual-piston calipers and a 200-mm (7.9-inch) rear disc present stopping energy and full the KX 125’s tire-and-wheel meeting.


The entrance suspension consists of standard 43-mm Kayaba forks (different mannequin years have a shorter 36-mm cartridge fork). On the again, the identical Uni-Trak® linkage rear suspension used on the ’83 125-cc bike and KLX 300s had been used however barely revised from its unique configuration to supply much less development.

The rear suspension was then mated to aluminum Kayaba shocks with a brand new bladder design (versus the de Carbon system utilized by the Quacker), lending to improved fade resistance, wheel journey, and smoother dealing with. Each entrance forks and rear shocks provide a beneficiant quantity of wheel journey – 300 mm (11.8 inches) and 310 mm (12.2 inches), respectively. They’re additionally compression- and air-adjustable. Nevertheless, that they had no adjustment for rebound.

Green 1999 Kawasaki KX 125 Dirt Bike


The general dimensions of the Kawasaki 125 Grime Bike are 2,155 x 825 x 1,200 mm (84.8 x 32.5 x 47.2 inches – L x W x H). Machines launched in Europe solely differ barely in measurement from these in North America – at 85.2 x 33.1 x 49.8 inches. Floor clearance is 340 mm (13.4 inches), whereas the wheelbase measures 1,455 mm (57.3 inches) ± 2%. The saddle sits at a peak of 930 – 940 mm (36.6 – 37 inches). Dry weight is 87 Kg (192 lbs).


It has a tubular semi-double-cradle metal body (with a 27.5° caster angle, 100-mm/3.9-inch path, and 45° steering angle). Normal Kawasaki 125 Grime Bike elements embrace handlebars, grips, chain and fork guards, and entrance and rear fenders. For the reason that bike doesn’t have a skid plate, getting a Devol Skid Plate (view on Amazon) will assist defend the underside of your car.

As for styling, Kawasaki adopted the polished look of Jeff Ward’s Works Machine – all besides the orange saddle, which was changed with a extra tasteful blue to suit the bike’s general aesthetic. Apart from the colour, the seat was additionally reshaped to sport an up-to-tank design. This alteration complemented the slimmer tank-and-shroud combo, making sliding ahead much less obtrusive and simpler. The buzzard-beak entrance fender turned extra rounded and had a skinny alloy brace beneath that prevented it from cracking if encumbered with mud.

Kawasaki KX 125 Value

The record worth of the KX 125 ranges from $4,949 to $5,099 for post-2000 fashions. Nevertheless, assets for the MSRP of older KX variations is usually a bit obscure. Nada Guides knowledge point out common resale values for all fashions solely till 2005, leaving out the final three manufacturing years of the two-wheeler. Pre-1985 fashions hold their worth fairly nicely, which is at the moment nearly double their unique record costs. Conversely, later-year variations of the bike can go as little as $250.

12 months – Trim – Mannequin Quantity Retail/Commerce-In Values
1974 – 1977 Kawasaki KX125/A3 $690 – $7,095
1978 Kawasaki KX125-A4 $1,110 – $8,725
1979 Kawasaki KX125-A5 $750 – $7,375
1980 Kawasaki KX125-A6 $750 – $4,645
1981 Kawasaki KX125-A7 $990 – $6,670
1982 -1984 Kawasaki KX125-B1/B2/C1 $750 – $4,645
1985 – 1991 Kawasaki KX125-D1/E1/E2/F1/G1/H1/H2 $750 – $3,990
1992 – 1993 Kawasaki KX125J1/J2 $250 – $1,830
1994 – 1998 Kawasaki KX125K1/K2/K3/K4/K5 $250 – $1,975
1999 – 2002 Kawasaki KX125L1/L2/L3/L4 $345 – $2,045
2003 Kawasaki KX125M1 $480 – $630
2004 Kawasaki KX125M2 $615 – $810
2005 Kawasaki KX125M3 $775 – $1,020

On-line, the saleability of the 125-cc bike appears to be overshadowed by the higher recognition of its successor, the Kawasaki KX250F. You would discover this pre-loved basic in good situation should you go to identified dealer websites or instantly to personal house owners. Anticipate secondhand costs to fall throughout the similar vary because the above. Something past $4,000 would often include mods, lights, or performance-enhancing elements.

From Off-Street to Road-Authorized

Whereas the Kawasaki 125 Grime Bike is undeniably an off-road machine, customers these days purchase the two-wheeler and switch it right into a metropolis journey. This could come as no shock, as enduro-style bikes have lately change into a best choice for leisure and metropolis driving. This part explains how one can convert your off-pavement bike to a day by day commuter.

DOT-Compliant Headlight

There are three options your headlight ought to need to be compliant:

  • Have excessive and low beam perform (and ideally actuated through an easy-to-reach swap)
  • Be clearly seen however shouldn’t be blinding to drivers or oncoming site visitors
  • Present ample mild distribution for each day and evening

You may select from halogen, HID, or LED lights on your headlamps. Nevertheless, word that halogen lights draw in your bike’s electrical system greater than LED does. Moreover, you have to to have a charging system to go together with your battery. In the event you keep on with halogen, be sure to get a brand new stator to assist energy the lighting system you’ll equip the bike with.

Whichever you select, I strongly counsel utilizing battery-powered lights to keep away from encountering dimming of lights when working low on the RPMs.

Brake Gentle & Taillight

Your brake/taillight ought to ideally be linked to a battery and stay lit for at least 20 minutes. Its mild needs to be seen sufficient to inform different drivers that you’re slowing down or attracting consideration when using through the day. Solely a single bike brake mild/taillight is required in sure states. To make certain, analysis your state/township pointers on brake and taillights.

When put in accurately, the taillight prompts when each the rear brake pedal and entrance brake lever are engaged. A banjo-bolt swap ensures this takes place by utilizing additional strain in an engaged brake line. In the meantime, mechanical swap choices work greatest for drum brakes. When you are at it, purchase an aftermarket bracket-fender combo for a completed take care of putting in the mandatory lighting.

Rearview Mirror

Fortunately, mirrors go nicely with the rugged look of the filth bike. Whereas just some areas require one working mirror, it will make sense to put in two. In the event you discover stem mirrors distasteful, it’s possible you’ll go for low-profile wide-angle mirrors or bar-end mirrors for appears to be like. These choices have a decrease profile than most varieties and nonetheless do a good job eliminating blind spots on either side of your filth bike.

Flip Indicators

Set up of flashers/blinkers could also be skipped in some states/areas should you use hand indicators. However to facet with warning, having blinkers with a self-canceling function is healthier because it allows you to give attention to the highway when making a flip. Discuss with particular state guidelines when mounting entrance and rear flip indicators. Moreover, be aware of the really useful peak and hole between the flip indicators throughout set up.

DOT-Authorized Tires

Equipping the KX with DOT-certified tires is a should, because the inventory rubber on the bike is ill-suited for using on pavement. Tires marked with the letters DOT on their sidewall, however, include additional layers of rubber and are highway-speed rated. Supermoto builds are a growingly in style method of changing an off-road car right into a dual-sport bike. And so long as sportbike tires match in your bike’s rims, they could be swapped for inventory rubber.

Horn – The 2 largest necessities when putting in a horn is as follows:

  • It should be audible from not less than 200 ft away
  • It should be electrical (some states reportedly permit non-electric horns to go inspection)

License Plate Bracket

Kits together with a substitute fender with a license plate holder and lightweight can be found on-line. Some choices don’t embrace a substitute fender. Whether or not you mount your license plate vertically or horizontally, a light-weight can be essential to make the plate clearly seen. Mounting an affordable LED strip above the license plate makes this doable.

Different road-legal requisites embrace a muffler, reflectors, full digital instrumentation, accurately vented crankcase, and different EPA-friendly emission controls. Putting in a fan or adjusting gearing for road use may be required. Relying on the situation of your bike (you probably have a secondhand wheeler), you might have to do some suspension and top-end work, in addition to a body restoration.

Essentially the most difficult factor about getting your KX 125 authorized on the highway is getting the paperwork/sign-off out of your native motorcar workplace. For extra necessities particular to sure U.S. states, take a look at this text on the Honda XR650R.

About Kawasaki

Kawasaki Heavy Industries, Ltd. is the maker of Kawasaki 125 Grime Bike and is broadly identified for its off-road autos, bikes, facet x sides, and watercraft. The Japanese agency is answerable for creating a number of the strongest and modern machines available in the market. Moreover, it’s a revered pressure on the earth of motorcycling.

The corporate has been on and off the Enduro bike scene for the previous few a long time. However with its latest product choices, the using neighborhood can’t assist however sit up for higher issues from its product lineup. Kawasaki’s priorities proceed to enhance aerospace and vitality techniques, hydraulic equipment, ATVs, motorized autos, transit, and private watercraft.

Conclusion – Kawasaki 125 Grime Bike Evaluate

All through its manufacturing, the Kawasaki 125 Grime Bike continued to obtain upgrades and enhancements. Kawasaki made additional styling modifications and ultimately eliminated the electrofusion coating that overheated cylinder heads and melted pistons. The agency changed this with T-Therapy, which improved the final well being and efficiency of the wheeler.

The Kawasaki 125 Grime Bike is a rock-solid off-road car. Certain, some mannequin years had their dips whereas others had been categorized as in-betweens. However general, it was higher than most of its competitors.

Due to this little trailblazer, high-performance wheelers just like the undisputed Kawasaki KX 500 got here into existence. Extra importantly, each newbie and skilled riders can now take pleasure in a extremely succesful and spirited all-rounder – whether or not on the streets or within the open air.

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