GONE are the days of rip snorting open class MX monsters. Now it's about getting the power to the ground, being rider friendly and comfortable over longer periods. When you roll out on to the track you know Kawasaki's KX450F is on your side, not fighting you the whole way.

Engine

Anyone that’s thrown a leg over a KX four stroke since 2007 would know that the motor underneath the green machine is an absolute ripper. Over the years Kawasaki has introduced its flawless EFI system and made constant improvements to the engine and its various components, to ensure its motor stays at the front of the pack.
This year the Kawasaki engineers came up with some modest changes to further improve the 2011 bike. With sound/noise pollution becoming more and more apparent in our sport, Kawasaki took a step in the right direction by changing the exhaust system in an attempt to reduce noise. To do this the muffler length was extended, and the muffler core diameter decreased.
To compliment the revised muffler, all new EFI/Ignition settings were implemented to increase low end response and punch off the bottom. The piston skirt was modified to increase performance yet still maintain the excellent durability that it had in 2010.

Out on the track it’s easy to come to terms with the user friendly power-band and smooth engine characteristics of the big bore KX. Low end power comes on in what feels like a 'metered' amount of power. It’s not strong and snappy, it’s very smooth and easy to use and a more mellow power curve off the bottom when compared to some of its competition.
As you build through the revs the mid-top echelon of the power-curve shines and the KX grows some longer legs as it revs out quite hard for a big bore four stroke.
It’s certainly not a bad thing that the green machine isn’t hitting as hard off the bottom, as it actually makes the bike a bit easier to ride and not so taxing on your body after a few hard laps around the motocross track. The power was plentiful when you needed it most as you screw on the throttle hard to make that fast exit out of a corner or for that bit of extra power to make it over the next obstacle. The engine and EFI setting make the KX450 very responsive at almost any RPM level. It’s quite easy to blip the throttle and find yourself in the peak RPM range and right in the meat of the power, all without the slightest hiccup or miss out of the intake system.

Chassis and suspension

The Chassis and Suspension set-up remain relatively unchanged on the new 2011 machine. The Kayaba suspension has had some minor changes with the internal valving, and we understand the chassis has received no real rider beneficial changes on the new model.

The big bore KX handles well out on the track. We played around with a few settings on the Kawasaki and managed to come up with a good base setting pretty quickly. We set the rider sag at 102mm and made sure all the clickers were in the standard position as per the recommended setting from the factory. Then we moved the forks so they were sitting 8mm up through the top triple clamp and once again set the clickers to the factory settings. On the tracks which we found to be smoother and more jump filled we stiffened up the compression setting in small amounts to make the most out of the travel on the bigger jumps.
Once the tracks got rough and nasty we went softer than the factory settings as the standard clicker settings seemed to feel a bit harsh in the changed conditions.

The rest

The standard handlebars on the Kawasaki are certainly a winner here at Cycle Torque, the Renthal 7/8” ’bars may not be twin-walls or tapered style bars, but for most riders out there the standard ’bars are just fine and the bend is very comfortable and easy to get used to. Bridgestone take good care of the rubber and supply the very popular M403/M404 combo as standard equipment. The front and rear brake systems on the Kawasaki work well and have no problems, but it would be a welcome addition if the decision makers at Kawasaki decided to include a larger 270mm front rotor as standard equipment. Anyone who has ridden a big bore 450 in recent times would probably agree with us by saying that today’s 450 off-road bikes can be quite a handful to try and pull up. It’s not to say that the KX doesn’t stop, it’s just that the braking power could be easily improved without too much research and development.

The final say

The 2011 KX450 is a great package straight off the showroom floor. The green machine has quality Japanese components from front to back and is a great bike for the average punter to work on.
To top it off quality on the KX looks a million bucks too, but only costs $11,699.
The engine and suspension is well set up for the average MX rider and most riders will easily adapt to the Kawasaki’s characteristics.
Any rider in the market for a new 450 motocross bike should certainly take a look at the 2011 KX450F.