Parallel test: KTM 250 EXC and 450 EXC

• Video

But why are we comparing motorcycles of completely different sizes, you may ask. If you haven't learned technical skills, you may have heard (re)learned in elementary school that a two-stroke engine can produce even more power than a four-stroke engine of the same displacement. Both theory and practice are not much different - because a two-stroke spark plug ignites every other stroke, but in a four-stroke engine every four strokes, the engine produces more power, and unofficially the test machines have the same maximum power of about 50 "horsepower".

Thus, in the E2 enduro competition class, riders can ride with two- or four-stroke engines with an engine capacity of up to 250cc. See In professional motocross, the former are almost gone, but not in enduro, especially in its extreme branch of races such as Hell's Gate, Erzberg and indoor enduro racing. So don't fall for the landfill!

From a distance of about ten paces, the test cars work the same way, and even if you look at the data on the external dimensions, equipment and fuel tank volume, they are similar in hair. A steering wheel, good (hard) hand protection, a plug on the left side of the fuel tank, simple switches and a small digital instrument panel are the same on the hair. The difference is revealed by the type of engine or. exhaust - a two-stroke has a twisted “snail”, a four-stroke has only a tube of the same thickness.

The larger exhaust makes the 4T harder to manually move (not surprisingly often done in the field), as the pot is too close to the handle under the rear wing, and also significantly heavier. You will feel the kilograms already when loading into the van! And while driving? After we woke up the cars with a kick (250) and pressed the red button (450) (the two-stroke engine always ignited after the first or second blow!) And twice, three times changed horses, opinions quickly crystallized.

Starting with a smaller displacement: Compared to clockwork two-stroke motocross machines of the same displacement, the EXC engine is very well polished even at lower RPMs. Even a very steep, seemingly impassable slope can be negotiated at medium speeds and in second gear, but the engine still lacks real responsiveness and explosiveness in this area. To release all the kilowatts, it needs to be turned into the upper rev range, when the character and sound of the block has completely changed - then there will be enough power (but not too much for a loaded enduro), and if we insist on full throttle, the accelerations of the test machines are comparable.

It is commendable that even if the engine is "switched off" at low speeds for a while, it wakes up instantly and without "trolling" if necessary. Because of its lighter weight, the suspension is mostly stiffer, so it needs a bit more power in the arms, especially when crossing successive short bumps where it's less stable than the 450cc version. Uneven power delivery, poor directional stability and stiff suspension are the reasons why driving is tiring, but, on the other hand, it pleases with its lightness and youthful temperament.

Almost once again, volume and breath in four strokes are reflected in the EXC 450, mainly in the way power is transferred to the rear wheel. While a two-stroke needs to be very precise when choosing a gearbox, the 450-tica is forgiving here. This was most evident when accelerating from a corner to longer jumps - when I entered a corner in too high a gear with a 250cc engine, I had to shift gears and press the gas pedal hard enough to get up enough speed to jump, and on car with an engine capacity of 450 cc. See. It was enough just to turn the lever, and the engine continuously, but decisively, went uphill.

We were happy to discover that the EXC 450 was no longer brutal, but very comfortable for the driver, so driving, despite the great power, does not require a lot of effort. The engine mates very well with the suspension, which is adjusted so that it picks up bumps gently, yet strong enough to keep the bike steady on bumps and withstand motocross jumps without crashing or bouncing. Interestingly Irt's opinion is that a 450 EXC with a properly redesigned suspension and removal of lightweight elements would be very suitable for amateur motocross riders. Why?

He says the average motocross rider is unable to tame and properly use explosive motocross 450s, so a character like the one EXC offers is a better bet. The only detail we would like to criticize is the insecurity of the engine. If, for example, you plan to drive among the sharp rocks of Istria at the race in Labin, be sure to buy a motor shield, as the (narrow) frame does not protect it enough. The 250 EXC does some of the muffler resonance, and the engine is smaller and therefore better hidden behind the frame, and it's half a centimeter further off the ground.

The second part of the test, which was not recorded in digital image and video format due to non-observance of driving rules in a natural environment (this is also not recommended for you), took place in the field. Maret and I rode 130 kilometers of cross-country in less than seven hours, of which the silent engines (we appreciate that) lasted a full four hours, according to the meter, and only confirmed the results of the motocross track. So - 450 EXC is more useful and versatile, and 250 EXC is livelier and EASIER.

When in the middle of a large stone-flavored train you have to manually turn or help fuel the "horses" uphill with your own donkey power, every kilogram is superfluous, and here the two-stroke engine plays the role of a more suitable machine. However, he is thirsty and wants two percent more oil in addition to fuel. At the first "checkpoint" he wanted half a liter more, and we set the consumption of 8 liters per hundred kilometers, while the consumption of a four-stroke engine on the same route stopped at 5 liters.

The drivetrain is good for both, even better for the 450cc enduro. equally strong in both. Yes, and that: the braking effect of the two-stroke engine is practically nil, so the brakes and the driver's wrist suffer a lot more when going downhill.

Two- or four-stroke? Most will be happier with a more expensive, more useful and more versatile four-stroke engine, but don't miss out on the cvajer if you don't mind fuel / oil mixture preparation and more uneven power distribution (engine responsiveness can be altered by replacing valve springs in the exhaust), especially if you like to challenge yourself in difficult terrain. We believe that our findings and information on the cost of services will help you make a decision. And a lot of fun from enduro fitness!

Face to face

Matevj Early

First of all, let me say that after a long time I rode an enduro motorcycle and this is on a motocross track. The gist of this test was to compare the two-stroke and four-stroke engine, because they compete against each other in the same category, and since I rode a 450cc four-stroke motorcycle last year. KTM of this volume. I was impressed with the smoothly distributed power, as the bottom isn't even a little aggressive, but it is quite responsive and bouncy.

The damping was too soft for my feel and for the motocross track, but the engine performed well in the pits and on landings. The bike itself is not a problem, only in closed corners it is a little more awkward than the 250. I am sure this bike will be ideal for amateur motocross riders when handling damping, as the fast and smooth ride did not tire me.

The 250 cubic foot two-stroke engine disappointed me a little. I tried to drive it at higher rpms, but nowhere was the power that the beast was supposed to produce. The ride was thrilling as the bike is lighter and therefore very manoeuvrable, but more tiring than riding a 450cc bike. See I think the 250 EXC is for two-stroke enthusiasts who already have a lot of knowledge to use that power in narrower applications and enjoy the bike's lightness and agility.

Matei Memedovich

Let's say I consider myself a Sunday racer and don't have the necessary fitness to deal with difficult terrain, so I feel better on a four-stroke engine that is more relaxed and indefatigable. However, since the pace of life is very fast nowadays and there is never enough free time, and since challenges bring challenges, and since even the steepest slopes should not remain invincible, I would prefer to opt for the (cheaper!) Two-Stroke Bee. 'for those two free hours a month. Its big pluses are lightness and maneuverability on the field. All you have to add is just the extra charge for the electric starter.

Marko Vovk

There is a difference. And that's great. As an amateur driver, the four-stroke EXC 450 was better suited to me because it is softer, consistently delivers power and is generally more comfortable to drive than the EXC 250.On the other hand, the EXC 250 is significantly lighter, but stiffer and therefore better for driving on terrain with more complex technical requirements, where fewer kilograms play an important role. Unlike the four-stroke engine, the two-stroke does not slow down on descents, and this is one feature that I find hard to get used to.

Matevj Hribar

Photo 😕 Matei Memedovich, Matevz Hribar

KTM EXC

Test car price: 8.700 EUR

engine: single-cylinder, four-stroke, liquid-cooled, 449 cc? , 3 valves, Keihin FCR-MX carburetor 4.

Maximum power: np

Maximum torque: np

Energy transfer: Transmission 6-speed, chain.

Frame: chrome-molybdenum tubular, aluminum subframe.

brakes: front coil? 260mm, rear coil? 220.

Suspension: front adjustable inverted telescopic fork White Power? 48, rear adjustable single shock White Power PDS.

Tires: 90/90-21, 140/80-18.

Seat height from ground: 985 mm.

Fuel tank: 9, 5 l.

Wheelbase: 1.475 mm.

Weight: 113, 9 kg.

Representative: Axle, Koper, 05/663 23 66, www.axle.si, Moto Center Laba, Litija – 01/899 52 02, Maribor – 0599 54 545, www.motocenterlaba.si.

We praise and reproach

+ powerful, agile and non-aggressive engine

+ stability, driving performance

+ ergonomics

+ quality components

- more weight

– more expensive services

- muffler too close to rear handle

- open engine

KTM EXC

Test car price: 7.270 EUR

engine: single-cylinder, two-stroke, liquid-cooled, 249 cm? , Keihin PWK 36S AG carburetor, exhaust valve.

Maximum power: np

Maximum torque: np

Energy transfer: Transmission 5-speed, chain.

Frame: chrome-molybdenum tubular, aluminum subframe.

brakes: front coil? 260mm, rear coil? 220.

Suspension: front adjustable inverted telescopic fork White Power? 48, rear adjustable single shock White Power PDS.

Tires: 90/90-21, 140/80-18.

Seat height from ground: 985 mm.

Fuel tank: 9, 5 l.

Wheelbase: 1.475 mm.

Weight: 100, 8 kg.

Representative: Axle, Koper, 05/6632366, www.axle.si, Moto Center Laba, Litija – 01/899 52 02, Maribor – 0599 54 545,

www.motocenterlaba.si

We praise and reproach

+ light weight

+ agility

+ ergonomics

+ quality components

+ motorcycle and service price

+ live engine

- more demanding driving

– lack of power at lower speeds

– fuel must be mixed

– exposure to exhaust gases

– the engine has no braking effect

Errors and malfunctions during the test: loosen the screw of the generating set, the headlight bulb is out of order

• Basic data

  Test model cost: € 7.270 XNUMX €

• Technical information

  engine: single-cylinder, two-stroke, liquid-cooled, 249 cm³, Keihin PWK 36S AG carburetor, exhaust valve.

  Torque: np

  Energy transfer: Transmission 5-speed, chain.

  Frame: chrome-molybdenum tubular, aluminum subframe.

  brakes: front disc Ø 260 mm, rear disc Ø 220.

  Suspension: front adjustable inverted telescopic fork White Power Ø 48, rear adjustable single shock absorber White Power PDS. / front adjustable inverted telescopic fork White Power Ø 48, rear adjustable single shock absorber White Power PDS.

  Fuel tank: 9,5 l.

  Wheelbase: 1.475 mm.

  Weight: 100,8 kg.

• Test errors: unscrewed the screw of the power unit, the headlight bulb is out of order

We praise and reproach

powerful, flexible and non-aggressive engine

stability, driving performance

ergonomics

quality components

a light weight

adroitness

motorcycle price and maintenance

live engine

more weight

more expensive services

muffler too close to the rear handle

open engine

more demanding to drive

lack of power at low revs

fuel should be mixed

exhaust gas exposure

the motor has no braking effect