Gilera KZ 125


Make Model

Gilera KZ 125


1990 -


Two stroke, single cylinder, reed valve


124 ccc / 7.6 cu-in
Bore x Stroke 56 x 50.5 mm
Cooling System Liquid cooled
Compression Ratio 13.0;1


28 Dell'Orto PHBH carburetors


Electric ignition with capacitive output
Starting Electric

Max Power

29.3 hp / 21.8 kW @ 9900 rpm

Max Torque

18 Nm / 13.2 lb-ft @ 10250  rpm
Clutch Multi-disc oil bath


6 Speed 
Final Drive Chain
Frame Diagonal double cradle tubular steel

Front Suspension

Fork traditional 36mm. Antidive adjustable

Rear Suspension

Hydraulic shock absorber adjustable in spring preload Court Cosso

Front Brakes

Single 240mm disc 2 piston caliper

Rear Brakes

Single 240mm disc

Front Tyre


Rear Tyre

Seat Height 760 mm / 29.9 in


126 kg / 277.7 lbs

Fuel Capacity 

Consumption  average

19.9 km/lit

Braking 60 - 0 / 100 - 0

14.4 m / 43.3 m

Standing ¼ Mile  

15.8 sec / 133.1 km/h

Top Speed

152.6 km/h

Presented at the Milan Show in November 1985 and sold in June 1986, KZ 125 is undoubtedly a quantum leap in the panorama of the 125 road and finally closes any previous connection with the 125 who had known the peak of development in 1985 with Honda NS-F and Cagiva Aletta Oro S1. The KZ raises firmly as the cornerstone of a new line of 125 road: the 125 Sport.

The 125 Sport is representing thus the evolution of species, and although the modern and the increasing engine power dramatically mark the evolution of the eighth of a liter, the real difference with the pre-KZ precursors was probably in the chassis, or in the department that more 'than any other forward the "presence" of the motorcycle driver. In this sense, the KZ was certainly comparable to an average displacement, a feeling that until then sixteen at the time could only dream of. Winner of the title "Bike of the Year 1986", KZ and the 'a movement that owes his existence to a mythical character and deserves a special section: Luciano Marabese. HRD legendary founder of Motor House who distinguished himself in the first half 'of the 80 for the production of high-performance 125cc craft and where the symbol and' an acronym for "Happy Red Devils", Luciano Marabese was the designer who revolutionized 'the Gilera production in the second half 'of the 80 imposing a modern and innovative design that made the school.

The KZ remained in production for four years until 1990, but as for the previous RV 125, the novelty introduced in the meantime from competitors and Gilera itself, soon made it obsolete.

Price in 1986: 4,200,000 Lira turnkey (295,000 Lira Chambers. Electric)

Colors (for all production): White saddle with red / black with red seat.

KZ Endurance

During 1987 was also presented a special version of KZ, which is the endurance that while sharing the same chassis and engine of the same KZ, had a different front fairing features a dual light then resumed from the next MX-1 and a cover- seat passenger.

Price in 1988: 4,430,000 lire (295,000 lire electric start)

Colors: White / Red White / Blue

The bike soon

The clean lines and setup guide with handlebars collected and Rearsets, KZ make the forerunner of the 125 sports, although the approach adopted by test driving Gilera is not too strenuous at all inclined to exaggerated cuffs and leg type motion from the track. The line of KZ and 'characterized by a half-fairing that leaves in sight and the engine is complete with the long belly of the wheels: This is a solution certainly guessed, but quite unusual for a 125. Another peculiarity 'of KZ and' the body that integrates monolithic upper tail and tank in one piece, although the tank is in fact simply hidden, being plastic. To allow access to the filler reservoir, the housing includes a hinged shell, protected by a lock, which also gives access to the oil tank and the expansion of the radiator, in turn protected by a movable interlocking tray that contains also the cosmetic bag of irons, and air filter housing. Oddly, battery, supported by appropriate frame anchored to the motor connections, and 'at the front of the belly fairing of KZ. This is an innovative and probably wanted to find a better weight distribution, but at the same time due to chronic lack of space: the KZ, in fact, not having the seat tilted and 'devoid of any useful utility room.

Another innovative solution devised by Marabese and 'expansion exhaust confined within the beams of the frame: in fact, with a turn of 180 degrees on the left, the exhaust manifold allows expansion to pass on the left side of the cylinder, just between beams of the frame, and then expand gradually under the shelf Hold-saddle up to join in the tailpipe coming out the top left of the tail. Finally, note the electrical instrumentation and controls, that once again shine for completeness, quality ', ergonomics and easy' read / use.


The frame and 'a modern double cradle beams square tubes made of steel and is' complete with a rear-seat shelf Reggi halves in ALUMINIUM 'and rake' of 26gradi el'avancorsa of 88mm. The 36mm fork, production Kettle, and 'together with the inevitable, and rather useless, anti-dive adjustable to three positions with the Allen wrench. At the rear there is a steel swingarm and suspension coupled with a progressive Court & Cossa, called Power Drive and preload adjustable. Note the different placement of the rods, now internal, compared with the previous suspension Mono Drive adopted on the RV. The braking system includes a production Grimeca 240mm single disc front end with twin piston caliper and a parallel rear disc of equal diameter, but with single-piston caliper. The beautiful lenticular aluminum wheels, both 16 "are produced Grimeca and have the following sizes: 100/80 front and 120/80 at the rear. The total weight of dry detected by Motorcycle and 'of 123kg.


The propeller of the KZ and 'the second evolution of the RV engine and actually in 1986 not only looks like the engine more' powerful class but also among the more 'treatable sweetness for delivery. Equipped with of course admission Reed (live in the cylinder), balancer, automatic mixer, liquid cooling and electric start on demand, the real news' of the engine Gilera APTS is the adoption of the system, which stands for Automatic Tuning Power System, valve and exhaust resonance chamber. The system, which are reminders of the ATAC Honda NS-F, has a mechanical centrifugal-through the expansion of metal balls countered by a spring, that until about 7500 rpm the exhaust valve closes gradually, and then decreasing gradually the volume of exhaust gases that are forced into the echo chamber, before leaving the collector. Past the 7500 rpm, the valve closes completely, excluding the resonance chamber and thus leaving the exhaust and of course free to go directly from the exhaust system expansion. That system, like Honda, and 'basically an ingenious system to vary the timing of discharge and then allow the adoption of a cylinder that sees change its diagram exhaust the number of turns, so keeping excellent performance at low and medium speeds, without compromising the high performance. Finally, interesting to note the cylinder 12 lights (2 of admission, 7 of transfer and 3 exhaust), the carburetor Dell'Orto PHBH 28 and the expansion and exhaust terminal.

With regard to performance, KZ check the ultimate in power and data speed and accelerations with a maximum power to the wheel to 23.77cv 9250giri and a speed 'record for the highest category of well-153.200 km / h. Only in the tests taken, and 400 meters from 50km / h, KZ recorded a time of 20.036 sec and a velocity 'output of 97.300 km / h, which appears to be slightly lower than the leading Aprilia AS-125R (19.157 seconds and 104.046 km / h).