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Title fight 2000 KX500 vs 2011 KX450F ANDY WIGAN




A decade after winning the last 500cc Aussie MX title ever staged, can the KX500 still claim to be the biggest, baddest dog on the moto block? Or has the new KX450F got something to say about that?


hort of a large-calibre semiautomatic weapon being waved in your face, few machines evoke more fear and respect than a 500cc two-stroke motocross bike. Products of Europe in the 1970s and evolved by the Japanese in the 1980s, these 500s epitomised raw, explosive, terrifying grunt. They were brutal, unapologetic and unforgiving, and

became the universal symbol for the hospital Emergency Ward in twowheeled disguise. But how relevant is that proscription of the 500cc two-stroke these days? Is the fear, respect and reverence once reserved for these 500s beginning to wane with the passage of time? Surely these rebadged relics from the late 1980s

can’t still be kings of a moto-jungle now populated by high-tech, alloyframed, fuel-injected 450cc thumpers. Or can they? Exactly how does the old KX500 – arguably the most powerful of all the 500s – measure up to Kawasaki’s latest Open-class motocrosser, the recently released 2011 KX450F? After all, the KX450F has itself established a reputation for

class-leading power ever since it was first released in 2006. Yes, the time had come for the two meat axes of motocross to stand toe to toe; to determine whether yesteryear’s prize-fighter is still packing a knockout punch, or whether the new-generation KX450F had finally earned the title of top dog.


BIKE HEAD-TO-HEAD Now all we needed to do was find a KX500 in good nick... Enter Brett Whale – former Kawi dealer and national race team manager, and a diehard Kawasaki tragic. We asked the question and he was all over it in a split-second. “Mate, I’ve actually got the KX500 Peter Melton won the Aussie 500cc title aboard back in 2000,” Whale enthused. “That was Peter’s last season on my team and the last time they ran the 500cc class in the Aussie Championship. She’s pretty much a stock bike, though it hasn’t been started for 10 years. It’ll need a new piston and some TLC, but I can get her going. Easy done. And watch out ... that thing is green Viagra,” he said, laughing maniacally. Working together with Kawasaki Australia’s Glenn Macdonald and Melton – who runs his own suspension tuning business these days – Whaley was true to his word. Within a week, the boys had brought Melton’s KX500 back to its former glory. The #1 machine was ready to rock. Melton was keen as mustard to put his resuscitated 500 back-to-back with the 2011 KX450F, and to compare the new 450 with the 2010-model he’d been getting around on. Transmoto test pilot, Danny Ham, also jumped at the opportunity. And en route to Queensland for the test, it suddenly dawned on Hammy that he’d actually run a close second to Melton in that 500cc title chase back in 2000, riding a ‘worked’ DR-Z400. This story just kept getting better and better! And adding to the amusement, neither Ham nor I had ever ridden a 500cc two-stroke around a motocross track. A natural terrain motocross track and a date with the DynoJet beckoned...



The first KX500 arrived in 1983 – air-cooled and old-school. It became liquid-cooled in 1985 and was gradually developed over the following few years. But by 1989, the KX500 was pretty much set in stone. Sure, its 43mm Kayaba fork was up-specced to a 46mm unit in 1996 and it got a few minor brake components updates over the next decade, but the last KX500 to roll off a production line in 2004 had seen little more than new decals and minor cosmetic changes for the final 15 years of its life. Yes, the KX500 had been caught in a time warp since 1989.

Having won the Australian Supercross Championship in ’92, ’94 and ’96, the Peter Jackson Supercross Masters Series in ’95 and ’96, and the Australian 250cc Motocross Championship in ’96, there wasn’t a lot left for Peter Melton to prove. So in 1999, in his early 30s, the Queenslander got together with longtime Kawasaki dealer Brett Whale and had a crack at the Australian 500cc Motocross Championship aboard a KX500. Melton won the #1 plate in 1999 and again in 2000, in what would turn out to be the last 500cc Championship ever staged


HAVE THE 2011 KX450F’S UPGRADES WORKED? Despite claims that the remapped ECU would create a more responsive powerplant, the 2011 450 actually delivers its power in a smoother and more linear way. It’s almost as if the Kawi engineers have tried to peg back the aggressive 2010 engine a few notches in the name of rideability. The new KX450F still boasts plenty of mumbo and response across the entire rev range, and it’ll still carry tall gears just as well as last year’s bike. But when Pro riders look to blast out of a deep, loamy berm, they’ll notice that some of the punch has been traded for traction. This year’s FIM-spec muffler creates a much quieter exhaust note, so it is possible the ECU is in fact more aggressive, in a bid to offset the more restrictive exhaust.

Whatever the case, it’s a win-win for punters and Clubman riders. The 2011 bike is quieter and more user-friendly. As for Pros ... well, they’re likely to fit an aftermarket exhaust system anyway and reclaim any snap that’s been stolen by the new muffler. Kawasaki didn’t detail the “frame upgrades” for the 2011 bike, and the only visible difference we can see is that the rear engine mounts/hangers are cut-down and appear thinner than last year’s – a tweak that suggests Kawi reckons they’ve got the frame pretty right nowadays. As with last year’s bike, the new 450’s engine and chassis is very predictable. The bike has a light, compact, nimble feel. Its suspension is compliant over the small bumps, with excellent progression at both ends and great bottoming resistance. Most impressive of all is the way the thing hooks up on slippery terrain

EVOLUTION OF THE SPECIES... THE KX450F in Australia. “People used to ask us for the engine spec we ran for my race bike in ’99 and 2000,” reflects Melton. “But the reality is, the thing was pretty much a stocker with a thicker gasket to reduce the compression, an FMF pipe and a shorter-geared 49-tooth rear sprocket so I could pull third gear off the line with the thing. “You know, it was pretty cool to hear the KX fired up again after all these years,” Melton went on to explain. “It’s the first time the bike’s been kicked over since I wrapped up the championship at Broadford in 2000.

She’d been sitting around in Whaley’s workshop for a while and raped of a few parts. So to freshen it up for this test, we fitted a new piston, a new ignition and a richer needle (AvGas was legal back in 2000, but it’s bloody hard to find these days!). The lines and seals on my original brakes were all perished, so we fitted some fresh components off a 2003 KX500. Same

goes for the carb and reed petals. I gave the suspension a service – just new seals and bump-stops and some fresh fluid. If I recall correctly, my fork springs were a couple of rates firmer than standard, and the shock spring was what she rolled off the dealer floor with. A good dousing of silicon spray finished off the job,” Melton said with a laugh.

It was a long wait, but the KX450F finally arrived in Australia in late 2005. Out of the box, that initial ’06-model machine was damn good and it immediately won magazine shootouts around the world. Let’s take stock of its evolution since…

a more explosive bottom and mid. The main chassis spars were downsized to reduce rigidity and weight. The 48mm KYB got substantial upgrades, and the swingarm got a new linkage ratio with unusual rising-rate that created an unpredictable rear-end.

2006 – Great all rounder. Strong, broad and user-friendly power. Forgiving handling, but Pro riders complained that its rear-end tended to squat and that the suspension blew through its stroke on big hits. Some conrod little-end failures.

2008 – Minor tweaks and fine-tuning. The frame copped some gusseting, the conrod was hardened for durability, a revised shift mechanism improved transmission feel, and the crank was balanced. New black rims, seat and decals were fitted, but the oddball linkage remained.

2007 – Changes to cam timing created

2009 – Kawi’s first fuel-injected MX engine produced huge horsepower gains, though power delivery was less aggressive than its predecessor. The linkage ratio reverted to a more conventional curve, the chassis was made slimmer and the bodywork was overhauled for improved ergos.

2011 KX450F – UPGRADES

2010 – The chassis got a stiffer headstem, revised swingarm, firmer spring rates and a firmer seat. The powerplant got new bridge-boxed piston, redesigned cylinder, updated camshaft, exhaust and clutch basket – all of which created a gruntier, more response engine.

• Revised ECU mapping for improved low-rpm response. • Tweaks to frame, and updated engine mounts/hangers to fine-tune chassis flex characteristics. • Quieter, FIM-spec muffler. • New, grippier seatcover. • Modified front chain slider. • Revising valving specs for fork and shock.


BIKE HEAD-TO-HEAD – perhaps a combination of the smoother power delivery and the fact Kawi has finally settled on a rising-rate linkage that works for the machine.

HAS THE KX500 AGED GRACEFULLY? Inverted fork. Check! Disc brakes with twin-pot callipers at both ends. Check! Just when you’ve almost convinced yourself the KX500 isn’t too archaic, you spot the droopy rear guard and crappy little footpegs. Hmm, old-school! Then there’s that pyramid-style fuel tank. What the? And for an eye attuned to modern-day alloy perimeters frames, that spindly little green chromoly tubing that houses the 500’s donk looks like it belongs on a mountain bike … and an old one at that! “Mate, it looks like a dinosaur, but it actually ain’t bad at all to ride!” This was the first thing Peter Melton said after a couple of laps aboard the 500 that he hadn’t sat on since wrapping up the title in Broadford 10 years ago. “It’s already rattled my fillings loose, but it ain’t bad.” Spoken like a true easy-to-please old-schooler who grew up on twinshock machines! For a young punk

more accustomed to late-model motocross bikes, the 500’s ergos would feel pretty damn foreign. It’s nice and narrow through the girth and radiators, but the curved seat makes it very difficult to move around freely in the cockpit and to load up the front-end through turns. The bars are high, the clutch is heavy and the footpegs are half the size of modern units.

DOES THE 500 HANDLE? Compared to the compact 450, the KX500 feels tall. And with a full tank of juice, it carries its weight much higher than the 450 does. That makes it harder to flick the 500 from side to side or to really feel on top of the front-end through sweepers. But aside from that, she still steers, absorbs bumps and hooks up very respectably. Sure, its suspension isn’t as plush as the 450’s, nor does it offer the same bottoming resistance, but it handles much more predictably than any of us would have imagined. Jumping the thing is another matter though, and it did take some adapting to. The 500 feels as light as the 450 in the air, but setting the trajectory of the bike off the up-ramp is a challenge.



WHERE DOES THE KX500 RULE? Where there’s traction, where it’s smooth, and where the bike can’t get out from under you. Which, when you think about it, whittles things down to a very small portion of most motocross tracks. No doubt about it, the 500 is still packing a lot more grunt that the 450, and it made light work of the four-stroke when we performed a few third gear roll-ons on a dirt road. But using that power – getting it to the ground – is another matter all together. The 500’s power comes on with all the subtlety of a sledgehammer, so you have no choice but the to short-shift through the gearbox and use the meaty part of the rev range. It’s your only hope of

You feel the X’s extra weight around a MX track, but it does a good job of passing itself off as a motocrosser.

The 450 gives up lots of grunt to its forebear, but its equally evident that the 450’s power is a lot easier to use.


PAUL FEENEY GROUP (07) 5596 9001

CF: STD smoothing: 5




















15 3




7 8 9 ENGINE SPEED (RPM x 1000)

2000 KX500 Max Power = 56.50 2011 KX450F Max Power = 47.54


Max Torque = 44.01 Max Torque = 31.83



TORQUE (ft-Ibs)

Of course, we had to put these two Open-class beasts on the dyno and get a cold, hard measure of their punching power. And what an intriguing comparo between two very different specimens. While the Paul Feeney Group Dynojet 250 tends to measure lower than most dynos (a peak of 50 and 60 horsepower for the 450 and 500, respectively, is probably a better indication of what these bikes produce), it’s the difference in how and where they make their power, and torque, that is most astounding. Note how the 500 has well and truly signed off by 7000rpm, which is where the 450 is just starting to get into its stride. And with more than 40ft-lbs of torque to tame between 4500 and 6700rpm, no wonder the KX500 is such a handful. That and the fact it power jumps by more than 20 horsepower between 4000 and 6000rpm!

Why? Combine all that grunt with a heavy flywheel and minimal engine braking, and you can afford to back off way before the takeoff and still clear a jump easily. The big two-stroke just keeps driving and tends to fly nosehigh until you adapt your style to suit. Hammy adapted so well to jumping the 500 that he almost had a massive endo when he first got back on the 450!

dialling the throttle on with any semblance of control. In loamy berms, its explosive nature is fantastic; in technical ruts, it’s diabolical! Back in 2000, Melton actually shortened the standard 14/47 gearing to 14/49 on his race bike so he could get off the line in third gear. He carried third for Broadford MX track’s entire uphill start straight, and for much of the rest of the track for that matter. Clicking back to second gear means taking your life into your own hands – well, just your right hand – and who the hell knows what first gear is doing on a 500. Honestly! With so much torque and big spaces between gears, it’s handy that you can get away with very few gear changes on the 500. But you do need to pay attention to what gear you’re in and when to shift as the power comes to an abrupt halt before 7000rpm.

Like to occupy the zone between ‘on’ and ‘off’ the power? Bad luck – the KX500 just ain’t designed that way.



2000 KX500 $9090 (RRP in 2004) No warranty

2011 KX450F $11,699 No warranty

499.0cc 86.0 x 86.0mm Liquid-Cooled Single-cylinder 2-stroke 8.4:1 – 7.4:1 5-speed 14/47 Wet, multi-disc, cable-operated 9.75 Litres Keihin PWK39

449.0cc 96.0 x 62.1mm Liquid-Cooled 4-valve, DOHC single, 4-stroke 12.5:1 5-speed 13/50 Wet, multi-disc, cable-operated 7.0 Litres Keihin EFI (43mm throttle body)

Kayaba USD 46mm, cartridge fork Kayaba, 16mm shaft

Kayaba USD 48mm, twin chamber Kayaba, 18mm shaft

110.0kg 1490mm 950mm

113.5kg 1480mm 960mm

Nissin, 230mm disc Nissin, 200mm disc

Nissin, 250mm disc Nissin, 240mm disc






“No doubt about it, the 500 is still packing a lot more grunt that the 450, and it made light work of the four-stroke when we performed a few third gear roll-ons on a dirt road.” FORMER PRO: PETER MELTON


32, 90kg, 180cm


Is the KX500 merely an anachronism that refused to disappear with grace in the early 1990s? Nope, it still rules the drag race and dyno charts against the best 450s on the planet. It’s one hell of an animal – violent and unforgiving!

43, 90kg, 182cm

43, 103kg, 183cm “I own a 2010 KX450F, so the first thing I noticed was how much quieter the 2011 is. It’s still responsive but feels to have lost a little punch with its new restrictive muffler. It was great to jump back on my old 500. Initially I was a big worried that it was going to feel like an old dinosaur, but it was a lot of fun to ride and better than I thought it’d be. I can understand why so many old-school guys are now putting a 500 engine in a late-model chassis. With lots of traction, I believe the 500 could still cut really good lap times. But on slick tracks, the 450 is both faster and a whole lot easier to ride. This comparo was a really good reminder that you need to have a lot of respect for the 500. Grab a handful of throttle on the wrong surface and it’ll bite. The 450 feels light, the brakes work well and much more tractable and easy to ride. It’s modern!”


“They’ve definitely made the KX450F easier to ride this year, and I was very impressed how well the rear-end hooks up and drives. After watching guys ride the big 500s back in the 1980s, it was quite a thrill to finally ride one around a motocross track. It’s got heaps of power and I’ve got to say it surprised me that it didn’t feel anywhere near as dated as I thought it would. I think I adapted to the 500 pretty quickly because I’ve always tended to ride low in the rev range and use the torque and meaty part of the power. And that’s how you have to ride the 500. There wasn’t a lot of traction on our test track, so that really played into the 450’s hands, but I’d love to ride the 500 on a loamy track with plenty of traction. It’d be scary, awesome and a handful, but it’d definitely give the 450 a good nudge. It’s really got me thinking about riding one of these 500s in a new frame.”

“The thing that struck me about the 500 was not so much its outright acceleration or how blindingly fast the thing was, but how delicate you need to be with the throttle application through slow turns. Dial in a fraction too much juice through a rut and the bike will disappear from underneath you in a split-second. Shortshifting helped, but even then the thing’s prodigious torque means it’s in go-mode the entire time. You have to be 100 percent focused every moment you’re aboard the thing, so it wore me out mentally and physically. The KX500 might not have changed since 1989, but it clearly hasn’t lost its attitude. And while it’s fun, it’s certainly not fast on a slick track. Not in my hands anyway. It actually made the fourstroke feel easy to ride and it reinforced the fact the 450 is nimble, predictable, has great brakes, a really slick transmission, and it puts its power to the ground brilliantly. Case closed. Then again, I’d love to repeat the comparo on a sand track!”

Which can be dangerous on up-ramps! The 500 likes tracks where you can turn, point and shoot, but is very difficult to ride around grasstrack sweepers with a trailing throttle. These 500s are designed to be on or off the power, and there’s little room for a bloke who likes it in between! All of which is exactly why most guys spent much of their time detuning their 500s and making them more rideable. Most added base gaskets to reduce compression. Many fitted

heavier flywheels. And CR500 owners found that the biggerdiameter KX500 carbs helped knock the edge off the CR’s power delivery at low revs. This made it more manageable through turns, before unleashing the power only when the bike was upright.

WILL THE 450 ALWAYS CUT FASTER LAPS? On most tracks, and in the hands

of most riders, the answer is an unequivocal (and predictable but ever-so-slightly disappointing) yes! Thanks to its nimble, lightweight feel, balanced and predictable suspension, sweet brakes, broad and responsive power, and prodigious ability to find traction even when there is little on offer, the KX450F has developed into a fine allrounder with very few chinks in its armour. It doesn’t take too many laps to establish the 500 still has a

significant power advantage over the 450, but it’s equally evident that the 450’s power is a lot easier to use, and the average guy will come out way ahead on the 450 on all but the loamiest of tracks. The 450 demonstrated amazing drive and tractability on our slick test track and was really easy to dial on and maintain cornerspeed around smooth, flowing arcs. And, unlike the 500, it can be ridden to good effect anywhere in the rev

range. It’s happily short-shifted on slick terrain or welcomes you to throw revs at it in power-sapping loam or on fast straights. The four-stroke’s engine braking also gives it the chassis a squatter, more anchored feel on the way into turns.

MORE ONLINE... For more footage of the track test, dyno session and rider feedback, check out


Title fight  

Issue 4's 2000 KX500 vs 2011 KX450F

Title fight  

Issue 4's 2000 KX500 vs 2011 KX450F