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Kawasaki KX 450 F Parts

By AS3 Performance

The Kawasaki KX 450 F is Kawasaki's premier-class four-stroke motocross bike and one of the most successful machines in motocross and supercross history, in production since 2006 across several major generations. At AS3 Performance we have tested and developed parts for the KX 450 F across all of those generations, from holeshot devices and silicone hoses to levers, rear brake pedals and anodised reservoir covers.

Which Parts Are Most Popular For The Kawasaki KX 450 F?

At AS3 Performance we have tested and developed parts for the Kawasaki KX 450 F across all of its generations. Our range covers holeshot devices, silicone radiator hoses, front brake and clutch levers, rear brake pedals, gear levers, and anodised reservoir covers that pull the look of the bike together. Whether you're prepping the KX 450 F for an outdoor national, replacing a part that has come to the end of its life, or refining the bike to a higher spec, you should find what you need in this category.

Holeshot Device

A holeshot device locks the front fork down at the start gate, lowering the front of the bike to keep the front end planted as it accelerates and reducing the tendency to wheelie out of the gate. It's a small part that makes a big difference to a rider's chance of getting ahead of the pack. Our holeshot device mounts to the left fork guard and is supplied with a template showing exactly where to drill the holes to mount the button. It releases automatically as soon as the front suspension extends through the first set of bumps after the start.

Available in green to match the plastics on the KX 450 F, or red to look great alongside our range of red anodised accessories.

Silicone Hoses

The OEM rubber radiator hoses on the KX 450 F harden and perish with age, and a hose failure on a hot moto is the kind of thing that ends a meeting. Our silicone radiator hoses are manufactured from high-quality 3-ply silicone with polyester reinforcement and a 4.5mm wall thickness, pressure tested to five times the standard working pressure, and far less vulnerable to puncture, perishing or impact damage than rubber. Most of our kits are available in four colour options, and some are also available as a Y-kit which eliminates the plastic joining piece and forms one seamless hose from three of the OEM hoses.

We supply silicone hose kits for the complete KX 450 F production range:

  • KX 450 F (2006–2008) — green, black or blue
  • KX 450 F (2009–2015) — green, black, blue, white or red
  • KX 450 F (2016–2018) — green, black, blue, red or white
  • KX 450 / 450 F (2019–2023) — green, black, blue or red

We always recommend installing these with a set of our stainless steel hose clips. Silicone hoses are softer than rubber and installing them with the OEM clamps can damage them. Our clips are designed specifically for silicone hoses with smooth inners and rounded edges so they can be fastened tight without damage.

Front Brake & Clutch Levers

The feel a rider has from the levers on a bike like the KX 450 F can be the difference between being comfortable and in complete control or making mistakes and being seconds a lap off the pace. This is why we offer three options of front brake and clutch levers for the KX 450 F.

  • Forged Front Brake & Clutch Levers — designed to be most like the OEM levers. The OEM levers are cast aluminium which can be brittle and snap in a crash; our forged levers are cold forged, which improves strength. Forged aluminium is slightly softer, so an impact that would snap an OEM lever will instead bend these, leaving you with a usable lever to finish the race. Available in a black anodised finish only.
  • Flexi Levers — manufactured from 6061 aluminium and, as the name suggests, they flex backwards on impact, helping prevent damage to the lever, master cylinder or perch. The spring-loaded system sits neatly on the underside of each lever and is protected by a black plastic cover. These have a flatter front edge where your fingertips sit, preferred by some riders. Available in black, blue (for some models) and green.
  • Factory Series Flexi Levers — our most advanced and adjustable levers. They have a similar feel to our forged levers but feature their own flexi design with the spring-loaded system built into the perch. The clutch lever has an on-the-fly adjuster wheel for quick clutch cable adjustment, adjustable reach settings, and a plastic insert on the clutch perch to prevent impact damage. Available in green or black, but only for the 2006–2018 models, as from 2019 the bike has a hydraulic clutch.

Rear Brake Pedals & Gear Levers

Just like the hand controls, the foot controls are something riders like to adjust to get a comfortable setting, which is why we offer two options for the rear brake pedal and gear lever kits. The gear lever is the same in both kits with a similar feel to the OEM lever, while the brake pedal has two different tip options. Our standard brake pedal has a spring-loaded tip that pivots on impact to reduce the chance of damage. For riders who want more of an OEM feel, our Factory Series brake pedal has a fixed tip, CNC machined from billet aluminium, that can be moved forwards and backwards on the pedal. Oversized tips are available for both pedals, as are standard replacement tips in all colours.

  • AS3 Gear Lever & Rear Brake Pedal Kit — matched set of forged levers with a gloss black anodised finish, available with green or blue tips as standard. Three fitments: 2006–2008, 2009–2015 and 2016–2026.
  • AS3 Factory Series Gear Lever & Rear Brake Pedal Kit — both levers are sand blasted before anodising for a textured matt finish, with grey tips as standard, available for the 2009–2015 and 2016–2026 models.

Replacing both at the same time costs less than two separate orders and gives you a matching pair of levers on each side of the bike.

Master Cylinder Reservoir Covers

The perfect way to add the finishing touches to the handlebar area on the KX 450 F is to replace the cast OEM master cylinder reservoir covers with billet anodised alternatives. Our covers are CNC machined from billet aluminium with an anodised finish and laser-etched AS3 Performance branding. Each cover sits flush against the reservoir and uses the existing OEM mounting bolts, so installation is a straightforward swap.

All are available in four colour options: green or black to match Kawasaki's factory colours, or red and blue for anyone looking to add custom touches or align with sponsor colours.

Which Parts Need Regularly Replacing On The Kawasaki KX 450 F?

Brake Pads — One of the most important parts to check as part of regular maintenance. Failing to replace worn pads will damage the brake disc and significantly reduce braking performance. We stock two compounds: AS3 Racing Series pads work well in all conditions and are the better of the two in slower, wet conditions, while AS3 Factory Series pads are designed for faster, hard pack tracks.

Brake Discs — Just like the pads, the discs need checking regularly. All of our brake discs have a minimum thickness measurement stamped on them so you can easily tell when it is time to change them. We offer both front and rear discs for the KX 450 F, and when fitting a new disc we always advise fitting new pads too.

Clutch Cable — The clutch cables can stretch over time, and you will notice a deterioration in clutch performance. Replacing the old cable with a new AS3 by Venhill Featherlight cable makes a big difference. They are manufactured from marine-grade stainless steel with a Teflon inner liner for a smooth, low-friction pull. Available in green or black.

More Information About The Kawasaki KX 450 F

The Kawasaki KX 450 F (sold simply as the KX 450 from 2019 onwards) is Kawasaki's premier-class four-stroke motocross bike and one of the most successful machines in motocross and supercross history. It was first introduced in 2006, with the most recent comprehensive redesign coming in 2019.

The current engine is a 449cc liquid-cooled four-stroke single with DOHC and four valves, a 96mm x 62.1mm bore and stroke and a 12.5:1 compression ratio, producing 53.1hp and 33.1 lb-ft of torque at the rear wheel. From the 2019 model year the bike has been fitted with an electric starter and a hydraulic clutch, both major upgrades from the previous generation.

The chassis is an aluminium perimeter frame. Front suspension is a 49mm Showa inverted coil-spring fork with 21-way adjustable compression, 22-way adjustable rebound and 305mm of travel. Rear suspension is the Uni-Trak gas-charged shock with piggyback reservoir and adjustable dual-range compression damping. Brakes are Brembo at the front and Nissin at the rear.

Wet weight is 112.6kg. The KX 450 has been raced to multiple championships, including AMA Supercross titles with Ryan Villopoto and Eli Tomac, and the MXGP Championship with Romain Febvre. Kawasaki update the bike on a regular cycle to keep it competitive at the highest level.

Kawasaki KX 450 F Parts FAQs

Is installing an AS3 Performance holeshot device worth it on the KX 450 F?

It honestly depends on what you are using the bike for. If you are taking racing seriously then yes, absolutely; starts are everything in motocross and anything that gives you an edge at the gate is worth the investment. If you are just using the bike for practice tracks at the weekend, then a holeshot device isn't really required. Using the bike for enduro? That one is still up for debate.

Which silicone hose kit should I order for my KX 450 F?

Use the year filter on the product page to confirm the kit matches your model year. The hose routing changes between generations, so a 2009 kit will not fit a 2019 bike. Each kit covers the full silicone radiator hose set for that generation and is available in a colour option to suit the bike's standard graphics or your preference.

Are AS3 forged front brake and clutch levers a direct OEM replacement?

Yes. The forged levers are designed as direct OEM replacements and use the original mounting points and pivot bolts on the master cylinder, so fitment is straightforward with no modifications. The 2005–2012 levers fit the older Nissin master cylinders, the 2013–2018 levers fit the updated master cylinders, the 2019–2023 bike has different hydraulics again, and the 2024 onwards levers work with the new Brembo front brake.

What's the difference between the standard and Factory Series AS3 rear brake and gear lever kits?

The main difference is the rear brake pedal. The standard pedal has a spring-loaded tip with replaceable stainless steel teeth (the same teeth used in our Racing Series foot pegs). The Factory Series pedal has a fixed tip that can be moved forwards and backwards on the pedal. The other notable difference is the finish: the standard levers have a gloss finish, the Factory Series levers a matt finish.

Do AS3 Performance reservoir covers come with screws?

Not unless shown in the photos and mentioned in the product description. Our reservoir covers are designed as direct OEM replacements and are compatible with the OEM screws and rubber seals. When installing, always use the correct size screwdriver to avoid damaging the screws, which is easily done and often seen on second-hand bikes.

Are the KX 450 F levers and pedal compatible with the KX 250 F?

For brake and clutch levers, yes, although the years can differ; in recent times the levers on the 450 have changed first, followed by the 250 a year or two later. For the rear brake pedal it's a no: both bikes have always had different rear brake pedals and gear levers since their introductions in 2004 (250) and 2006 (450). Always check fitment on the individual product page before purchasing.

How can I improve the look of my KX 450 F?

Some simple, cost-effective visual upgrades are a selection of our anodised accessories: reservoir covers, oil filler plug, front brake line clamp, engine plug kit and an oil filter cover make a great base to start from. Later you can add a matching rear brake and gear lever kit, axle blocks and billet clutch and ignition covers.

What can I do if I can't find the Kawasaki KX 450 F part I'm looking for?

Our product range is constantly changing and evolving, and both our suppliers and ourselves are always developing and adding new products to the range. We work closely with riders, teams and customers to refine and improve our product offering on a daily basis, so if there is something you're looking for that you can't find on our website, feel free to contact us to discuss further.