First off, let’s start by saying 450cc engines make for big, fast, and serious bikes. They are for advanced riders who want to go as fast as possible. For the most technically designed, high spec. bikes on the market specifically created for racers. They are heavy, difficult to control, and can reach speeds of over 100 mph fairly quickly. Put simply, unless you are all about serious, high-intensity racing, these bikes aren’t for you.
To be frank, even a 250cc bike is only suitable for a medium to intermediate rider who has the basic skills down. If you’re a beginner, you will want a 125cc bike or less – and that’s still only for adults or young adults.
So, with that in mind, here are our three picks for advanced racing bikes with a 450cc engine. These are three of the quickest, and most expensive, bike on the market. All models discussed here are the latest 2021 releases, and we will be comparing them as we go.
KTM 450 SX-F:
The latest SX-F update features revised ECU (Engine Control Unit) mapping, improving several aspects of the vehicle’s performance. It also comes with a renewed suspension system, boasting all the great features of last year’s model and much more.
The engine is a single-cylinder, liquid-cooled, 449cc, Single Overhead Camshaft (SOHC). This beast of an engine can soar up to a sky-high top speed of 123mph and delivers 54.8 horsepower. The KTM slogan isn’t “ready to race” for no reason. With all this power does come the downside of some extra vibration compared to the other bikes discussed here, as some riders have noticed.
Like every bike on this list the SX-F is a four-stroke engine, meaning it delivers power every four turns of the crankshaft. What this technical aspect means in reality for the rider is that it delivers power in a much smoother, more drawn-out way.This certainly doesn’t mean that the bike is any slower; it may create less torque than a two-stroke, but it does mean that the bike can be used more precisely by the rider in moving through the gears.
The SX-F in particular, though, does have a longer, more predictable power delivery, making it slightly easier to control than the other bikes.
The braking system this year is powered by a 260mm disc with a Brembo 2-piston caliper on the front, with a smaller, 220mm disc and one piston on the back wheel.
Clocking in at 234 pounds, the SX-F is one of the lightest of the bikes in the 450 class. With the lightweight frame and the finely tuned, updated suspension balancing, this bike handles bends with grace and manages to bolt through the straights at high speeds in a decent straight line.
You can get the 2021 KTM 450 SX-F for around $10,200.
The Austrian manufacturer’s flagship bike this year has once again refined its capacity for swift handling, making it perhaps one of the easiest to handle in the class. Like the KTM 450, it’s pretty lightweight at 237 pounds – only slightly heavier than its rival. The bike has been lowered 10mm from the 2020 model, again allowing for swifter movement and an overall seat height of 37 inches.
Its engine – a single-cylinder, SOHC, liquid-cooled, four-stroke – has had no mechanical updates since last year’s release. It does, however, have many customizable settings which allow the rider to modify the power delivery depending on preference and track-type. This addition makes it a far more user-friendly bike.
With 55 hp, it can make it’s way up to a top speed of around 112mph, a little slower than comparable bikes, but nothing to be balked at.
It’s front and rear suspension is also fully adjustable, again permitting for highly customizable experience.
It’s Brembo caliper braking system is identical in size and power to the SX-F, making them both quick stoppers.
It costs a hefty $11,859.
The 2021 model of the Monster Energy Cup winning, Motocross winning KX 450, is an improved version of an already classic bike. Only very slight adjustments have been made: the lever pull on the clutch is easier to handle, it’s throttle response has become quicker and the suspension can absorb the track better than ever. Further, the ergonomics and proportions of the bike have a better feel to them, allowing for a more fluid rider experience all round.
The engine, whilst overall very similar to the other two bikes, differs in one important regard: it’s a double overhead camshaft (DOHC), rather than a single. Assigning four valves per cylinder rather than two facilitates an easier intake and exhaustion of fuel and gases in and out of the cylinder. This creates a performance advantage – the KX450 has 63 horsepower – the highest here. The DOHC also increases fuel efficiency.
On the other hand, since an SOHC uses less parts, the FC450 & the SX-F are both lighter in weight, more reliable and easier to repair.
The braking system uses a 270 mm disc, Nissin 2-piston caliper in the front and a 250mm disc with 1 calliper in the rear.
As mentioned, the KX450 is the heaviest here at 246 pounds.
The lime-green monster will set you back $10,799.
As mentioned, these are the flagship racing bikes for three of the best manufacturers of dirt bikes. That means that these three bikes are the most powerful and fine-tuned you can get, and can only be operated safely by advanced riders with precision and skill.
The Kawasaki has the most powerful engine, and the most trophies to boast, but it’s heftier engine makes it a relatively heavy bike compared to the other two. The engine also makes it harder and more expensive to maintain.
For those that want to perfect their movement, the Husqvarna offers the most. It’s highly customizable engine and suspension settings and lightweight frame makes for the best handling here.
However – the KTM is a rocket, with a great powerband and is the lightest bike of the three. Combining the best of the other two bikes, and being the cheapest bike here – I have to declare the KTM 450 is our pick of the 2021 450 class.