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Comparison test: 450 cc motocross

Off-road comparison test in the 450 class

Cylinder tilted backwards, cylinder head turned, tank moved downwards: Yamaha brought the YZ 450 F into shape with original ideas. How does the MX1 bike hold its own against the competition??

VMatch test: 450cc motocross

Even if the adage is already worn out, its truthfulness cannot be denied: Nothing is certain except change. This also applies to technology in off-road sports. It was not until the 2006 season that the last two manufacturers, KTM (250 SX-F) and Kawasaki (KX 450 F), completed the final departure of the two-stroke engine from the most important motocross classes.

Comparison test: 450 cc motocross

Off-road comparison test in the 450 class

Kawasaki KX 450 F + video

by Diego

Amazing: With a strangely tuned rear suspension, the Kawasaki as last year’s test winner in this comparison screwed up a safe top position.

With the pressure of the defending champion from last year’s motocross comparison test in MOTORRAD (issue 26/2008), the Kawasaki enters the race. A first-class tuned injection system, a lively, yet easily manageable engine, excellent starting behavior and excellently tuned spring elements formed the combination for class victory a year ago. Nothing significant has changed on this basis in the new edition – with one exception.

by Diego

Joyride: All Japanese manufacturers are now relying on the injection system from Keihin.

Compared to that exemplary balance, the suspension setup of the 2010 KX has lost a lot. While the Kayaba fork is still one of the finest in terms of responsiveness, the rear is a mystery. In all driving situations, the hindquarters work their way far into the suspension travel, conveying a chopper-like driving experience. It can hardly be due to the spring preload, the standard setting – nine centimeters of sag with driver – is at the upper limit of the usual setting values ​​(10 to 10.5 centimeters). It is understandable that the Kawasaki therefore has to give up when it comes to handling and turning behavior. Too bad, after all, the rest of the overall package is still convincing.

Technical specifications

ENGINE:

 characteristics Water-cooled, single-cylinder, four-stroke dohc engine with four valves per cylinder
 Displacement (in cm³) 449
 Bore x stroke (in mm) 96 x 62.1
 Compression ratio 12.5
 Performance (measurement)
 35.2 kW (48 hp)
 at speed (in / min) (measurement)
 8250
 Carburetor / injection,
 Diameter (in mm)
 injection
43
 Corridors 5

LANDING GEAR:

 characteristics  Bridge frame made of aluminum
 fork  Kayaba
 Guide tube diameter (in mm)
  48
 Strut  Kayaba
 Weight (in kg) (measurement)
  108
 Price without additional costs (in euros)
  789

Suzuki RM-Z 450

by Diego

Billich, do I want? For the 2010 season, Suzuki is significantly increasing the tariff for the previous price breaker. Without the advantage of the special offer, it won’t be easy for the more casually processed RM-Z – even if its concept is up to date.

The bad news first: The price advantage that the yellows have been able to throw into the scales has shrunk. At 7490 euros, the RM-Z is still the cheapest in the field. Be that as it may, with injection, dohc engine and an aluminum bridge frame modified for the season, the Suzuki is technically on a par with the competition. Above all, the engine that flaunts with full thrust from the lower rev range characterizes the yellow.

by Diego

The engine of the Suzuki is also state-of-the-art, as is that of the Kawasaki.

The single, though somewhat rough, pushes out of the curves with pressure, skilfully overriding his only moderately pronounced revving pleasure with a strong middle area. The neutral handling in tight turns, including sufficient stability on bumpy straights, is pleasing. And that despite the fact that Showa suspension elements are less sensitive than the competition from Kayaba. The bottom line is that there are no ups and downs either – that results in fourth place on the balance sheet with the Kawasaki.

Technical specifications

ENGINE:

 characteristics  Water-cooled, single-cylinder, four-stroke dohc engine with four valves per cylinder
 Displacement (in cm³)  449
 Bore x stroke (in mm)  96 x 62.1
 Compression ratio  12.2
 Performance (measurement)
  38 kW (52 hp)
 at speed (in / min) (measurement)
  9000
 Carburetor / injection,
 Diameter (in mm)
  injection
 43
 Corridors  5

LANDING GEAR:

 characteristics  Bridge frame made of aluminum
 fork  Showa
 Guide tube diameter (in mm)
  47
 Strut  Showa
 Weight (in kg) (measurement)
  109
 Price without additional costs (in euros)
  749

Yamaha YZ 450 F + video

by Diego

The much-noticed: its unorthodox technology moves the Yamaha YZ 450 F into the center of interest. The change in character due to the much more aggressive power delivery has little to do with the innovative chassis and engine layout.

The completely turned inside out Yamaha YZ 450 F has finally said goodbye to the gentle, quiet appearance. The loud exhaust noise and, above all, the intake snorkeling from the air filter box behind the steering head, reminiscent of the Husaberg enduros, are a permanent reminder of the new era. Which the engine clearly underlines. From the lowest engine speed to the highest regions, the unit, which operates with four instead of five valves and injection, is defined by impressive power. Especially in the upper speed range, the Yamaha accelerates vehemently, with the test field’s record value of 54 hp, demands a firm grip on the handlebars – and on terrain with little traction for a finely dosed throttle. A characteristic that will please the high society of driving, but will also show some amateur crossers the driving limits. In terms of suspension, the YZ stayed true to itself – combining the demands of amateurs and experienced pilots. Excellent response behavior and a significantly more progressive damping setting of the Kayaba spring elements compared to the previous model create more reserves without having to make any significant compromises in terms of comfort.

by Diego

Yamaha YZ 450 F air filter.

Especially since the handling – the optimization of which was ultimately the focus of the design effort – the opinions differ. Ergonomically, the 2010 model does not necessarily bring an improvement, as the radiator cowling is uncomfortably wide due to the airbox. What has remained, however, is the typical Yamaha, front-wheel-oriented, sometimes somewhat top-heavy driving experience. The 450 turns as if on rails, remains neutral at the apex of the curve and can be accelerated stoically calmly out of the bends. A characteristic that inspires confidence and that suits many. However, the new model does not meet expectations of a new dimension in agility, if only because of the weight that has increased by four to 108 kilograms compared to the previous year’s model. There is third place for the mix of a traditional driving experience and the latest technology.

Technical specifications

ENGINE:

 characteristics  Water-cooled, single-cylinder, four-stroke dohc engine with four valves per cylinder
 Displacement (in cm³)  449
 Bore x stroke (in mm)  97 x 60.8
 Compression ratio  12.5
 Performance (measurement)
  39.9 kW (54 PS)
 at speed (in / min) (measurement)
  9250
 Carburetor / injection,
 Diameter (in mm)
  injection
 44
 Corridors  5

LANDING GEAR:

 characteristics  Bridge frame made of aluminum
 fork  Kayaba
 Guide tube diameter (in mm)
  48
 Strut  Kayaba
 Weight (in kg) (measurement)
  108
 Price without additional costs (in euros)
  8495

KTM 450 SX-F

by Diego

In 2011, the change to injection and diversion is expected. The SX-F is already a good bike.

The KTM starts the new season only slightly changed. Nobody takes it against her that the Austrian is the only 450 model to be fed with a carburetor. On the contrary. With an electric starter as well as beefy performance characteristics and an excellent gearbox, the SX-F’s engine moves to the top of the engine rating. In terms of character, the handy and agile chassis in turns, which sometimes tends to be a little nervous in fast passages.

by Diego

Close: KTM is the last manufacturer to still rely on the flat slide carburetor, and the only one on a directly hinged strut.

As a bonus, there is also an excellent front brake. That fits. What it suffers from: The large series distribution of the spring elements from WP Suspension. MOTORRAD knows better things from the internal KTM supplier than the uncomfortable PDS strut and the uncomfortable fork of the test machine. Nevertheless, the overall package is right. second place.

Technical specifications

ENGINE:

 characteristics  Water-cooled, single-cylinder, four-stroke dohc engine with four valves per cylinder
 Displacement (in cm³)  449
 Bore x stroke (in mm)  97 x 60.8
 Compression ratio  12.5
 Performance (measurement)
  38.3 kW (52 hp)
 at speed (in / min) (measurement)
  9000
 Carburetor / injection,
 Diameter (in mm)
  Carburetor
 41
 Corridors  5

LANDING GEAR:

 characteristics  Single-loop frame made of tubular steel
 fork  WP suspension
 Guide tube diameter (in mm)
  48
 Strut  WP suspension
 Weight (in kg) (measurement)
  107
 Price without additional costs (in euros)
  849

Honda CRF 450 R.

by Diego

Knowing where: Small changes (coordination of fork and mapping) paved the way for the Honda to return to the podium.

After a complete renovation last year, the red one enters the ring only gently retouched. What is immediately noticeable: the technicians got the unruly starting behavior of last year’s model under control. The single shoots off – cold or warm – after the second kick on the kickstarter at the latest. And from the very first few meters, the 450 series shows that it will remain true to its conceptual reorientation in 2010. The Unicam engine pushes out of the lower speed range, powerful and yet easily controllable at all times, and is at its best in the middle regions.

The fact that the unit cannot continue this thrust in the upper area is most likely due to the pleasantly quiet exhaust system. Amateurs get along brilliantly with this performance characteristic, while professionals know how to help themselves with retrofit silencers. What does not sound spectacular, drives like that, and in the most positive sense. No motocross track can be circumnavigated more effortlessly and efficiently than with the CRF engine. With one exception: Tight clutch springs require an extremely courageous grip on the clutch lever. But it also remains at this point of criticism of the engine.

by Diego

Handling, steering precision and nice details like the steering damper are unparalleled.

Last year’s model has already proven that the extremely compact CRF sets the bar in terms of handling. The Kayaba technicians have now tightened the fork’s compression damping, which had turned out to be too soft last year, thereby balancing the CRF noticeably better, especially in braking waves. Add to this a unique steering precision, which is at least four kilograms less weight than any competitor model and the first-class ergonomics and workmanship typical of Honda the new boss in the ring of 450 crossers: Honda CRF 450 R.

Technical specifications

ENGINE:

   
 characteristics  Water-cooled, single-cylinder ohc four-stroke engine with four valves per cylinder
 Displacement (in cm³)  449
 Bore x stroke (in mm)  96 x 62.1
 Compression ratio  12th
 Performance (measurement)
  36.1 kW (49 hp)
 at speed (in / min) (measurement)
  9750
 Carburetor / injection,
 Diameter (in mm)
  injection
 50
 Corridors  5

LANDING GEAR:

 characteristics  Bridge frame made of aluminum
 fork  Kayaba
 Guide tube diameter (in mm)
  48
 Strut  Kayaba
 Weight (in kg) (measurement)
  103
 Price without additional costs (in euros)
  7910

Current changes at a glance

by Diego

They all aim high, but not all are technically up to date.

Honda

  • Suspension set-up modified
  • Mapping optimized

Kawasaki

  • Bigger cooler
  • Exhaust manifold shortened by 40 mm
  • Modified deflection

KTM

  • Five instead of the previous four courses
  • Ride height lowered by 10 mm (strut shortened, steering head welded higher to frame)
  • Elbow with resonance chamber

Suzuki

  • Camshafts changed
  • Mapping revised
  • Steering head angle flatter
  • Frame profiles modified

Yamaha

  • Cylinder tilted back four degrees
  • Cylinder head rotated 180 degrees
  • Bore / stroke ratio changed (97 x 60.8 mm 2009: 95 x 63.4 mm)
  • Four instead of five valves
  • Petrol injection instead of carburettor
  • Air filter box behind the steering head
  • Tank placed further back and lower

Test result: 450 cc motocross

by Diego

The fight for first place.

1st place:
Honda CRF 450 R.
An excellently tuned engine, the lowest overall weight and above all first-class handling add up to the homogeneous overall package.

Place 2:
KTM 450 SX-F
Only one point is missing to win. What if the SX-F had more responsive suspension? Nevertheless: powerful engine, electric starter and great handling are convincing.

Place 3:
Yamaha YZ 450 F.
Success or failure for the spectacular concept? One thing is clear: the Yamaha has changed from a softie to a professional device. Whether that’s good is a matter of taste.

4th place:
Kawasaki KX 450 F
The field is tight. A year ago it took the win, now a strangely coordinated hindquarters reaches through to the rear – despite the lively engine and successful peripherals.

5th place:
Suzuki RM-Z 450
No doubt the RM-Z is good. But in terms of workmanship and smoothness, it lags a shade behind. And: it has given up its previous price advantage.

Drawing: archive

The performance diagram of the 450 series.

Overall rating:

 maximum number of points
  250
 Honda CRF 450 R.
  213
 KTM 450 SX-F
  212
 Yamaha YZ 450 F.
  207
 Suzuki RM-Z 450
  206
 Kawasaki KX 450 F
  206

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