It’s funny looking back at the 2009 Kawasaki KX450F because, by today’s standards, it would probably be considered one of the more manageable and rider-friendly 450s on the market. Back then, however, it was still regarded as a serious handful. The previous carburetted 2008 model was infamous for its brutal power delivery and aggressive hit, so when Kawasaki introduced fuel injection in 2009, along with a slimmer chassis and a range of engine updates, the bike became noticeably smoother and easier to ride. That didn’t mean it was soft. Far from it. The KX450F still packed enough punch to satisfy anyone brave enough to twist the throttle, but it delivered that power in a broader, more controllable way.

In many ways, the 2009 model marked the beginning of Kawasaki’s shift towards making the KX450F faster through rideability rather than sheer aggression. The engine introduced that year remained largely unchanged for several seasons, receiving only minor updates until the all-new model arrived years later. It offered a strong, wide rev range with plenty of torque and top-end power, making it a formidable motocross machine without the explosive nature of its predecessor.

The suspension both front and rear were quality KYB units, with the KYB closed-cartridge forks up front that still receive plenty of praise to this day. The link-type KYB monoshock on the rear came with plenty of adjustment in the way of 22-position rebound and compression adjusters, as well as a high-speed compression adjuster and a spring preload adjuster for setting rear sag.

I personally owned and raced a 2011-model KX450F and was impressed with both the power and its delivery, as well as how well the suspension worked. However, I upgraded the front brakes to a larger disc for more stopping power. In their day, I thought the bike cornered well, but given what we now know, I feel it was harder to turn than the later models.

Mechanically, I never had any problems with my bike and raced it for two seasons. The KX does, however, have a reputation for seizing camshafts if you over-tighten the cam caps or fit the oil filter backwards. This is more of a mechanic error than a manufacturer fault. If you happen to be changing your oil filter, take special care to fit it in the correct direction. If you do seize the camshafts, the only successful fix is usually to replace the cylinder head, which is a costly exercise.

When looking to buy a second-hand KX450F, make sure it starts easily, idles cleanly and has no unusual engine noises. The engines are generally strong, but they can deteriorate quickly if neglected or run with dirty oil. Make sure the air filter has been cleaned regularly. The valves are reasonably durable, but they still don’t like chewing on dust.

I have also seen a few issues with condensers failing on these bikes. The plugs can fill up with water and dirt and begin to corrode, or the wires can snap where they enter the condenser. If this happens, the bike may start but struggle to idle, refuse to rev cleanly and cough and splutter under throttle.

As these bikes are now well over a decade old, wheel bearings, linkage bearings and steering-head bearings can all be showing signs of wear. Check that nothing is seized or excessively loose, and make sure you take the bike for a proper ride to confirm it selects all gears correctly.

New

2008 $11,590

2009 $11,599

2010 $11,599

2011 $11,699

Second Hand

2008 $3,700 – $4,400

2009 $3,900 – $4,650

2010 $4,100 – $4,850

2011 $4,250 – $4,050

Market Equivalents

08-11 Honda CRF450R

$3,900 – $5,400

08-11 Yamaha YZ450F

$4,000 – $5,600

08-11 Suzuki RM-Z 450

$3,600 – $5,500

08 – 11 KTM 450 SX-F

$4,200 – $5,850

Frame:

The KX uses an aluminium frame with a removable aluminium subframe. The frame is lightweight yet strong.

Brakes:

The brakes on the KX both front and rear are hydraulic with single petal shaped discs. The caliper on the front is a twin piston floating caliper but the one on the rear is a single piston floating caliper.

Engine:

The engine is a 450cc water cooled, double overhead cam engine with a four valve cylinder head and shim and bucket type tappets.

Suspension:

The front and rear suspension are both made by KYB with a fully adjustable link type shock on the rear and fully adjustable closed cartridge forks on the front.

Weight:

The KX comes in at a claimed wet weight of 113kg.