The 400 and 520, in EXC and SX trim, will spearhead the company’s efforts as four-stroke technology continues to make in-roads into traditional two-stroke markets.

These bikes have been developed from scratch and are aimed the market created and dominated by Yamaha since the release of the YZ and WR400 models in 1998.

KTM have offered four-stroke models in the past but they have been aimed more at the traditional trail/enduro market. The new models use a totally new motor that develops much more power and is much smaller and lighter than ever before.

Indeed, they are so compact they are narrower than even the current 250 engine fitted to the 250SX motocrosser (which Cycle Torque has tested - see page 32).

This compact design was an engineering priority, because the company wanted to use the chassis of the SX/EXC two-stroke range, because it’s a no compromise package. There have been some minor changes to the existing frame, like the double wishbone downtube and modified engine mounts, but these modifications take nothing away from the performance of the chassis.

As you would expect of brand new competition bikes, the new machines are very light - about 112kg dry. So it might surprise some that there’s an electric leg fitted as standard equipment to the EXC range, while it’s an option on the two SXs.

The new bikes are heavily based on the machine Shayne King used to take third overall, including one win, in the world 500 motocross championship this year.

The 400EXC also enjoyed great success, taking both first and second overall in the enduro world championship 400cc 4-stroke class, and second overall in the open class. And that was all in the first year of racing the new machines. KTM’s commitment to racing has definitely helped develop the new machines and bring them to production so soon.

All the 400s and 520s are fitted with a kick starter; the button is termed ‘electric assist’. To keep the weight down the system only has the capacity for limited attempts, with the battery giving up after about twenty goes. KTM opted for this system to save weight – the starter motor is about half the weight of the one used in older KTMs and the battery is tiny. At the launch starting was never a problem, and an electric leg certainly makes life a whole lot easier if you stall the bike unexpectantly - sometimes you can get going again without even putting a foot down.

The battery is conveniently located in the top of the airbox which doesn’t cause a problem as the airfilter is accessed form the side.

At Picton we were able to ride both the 420 and 520EXCs. The only SX version in the country was the one Shayne King would use to annihilate the opposition a few days later at the Lithgow Thumper Nats round, so there’s no doubt they will be ultra competitive.

The 400EXC is a great all-round bike that feels very light and easy to ride. The motor starts easily with or without electric start (just don’t use any throttle or it will easily flood).

Although it loves being revved hard, the power delivery is very smooth. This bike will suit a wide range of riders looking for a fun bike to ride anything from cruisy trails to serious enduros and even some motocross. The motor doesn’t have a big hit of top-end power like a Yamaha WR400 and fits in somewhere between an XR400 and the WR, although peak output would be closer to the Yam.

If the power sounds a bit disappointing, the handling will make up for it. The 400EXC is awesome. It feels (and is) very light, with the White Power upside down forks and PDS shock from the same manufacturer balancing the bike beautifully, this is one of the easiest bikes there is to jump on an go fast. To top it off the the brakes are the best around and the hydraulic clutch is great.

The XR400 hasn’t had too much competition in the past and has been the best selling trail bike in Australia for ages. Times are changing and the KTM 400EXC is some serious competition.

The 520 EXC is the big bad brother of the 400. It offers the extra raw power that bigger, badder, riders are looking for.

As I hopped on the machine a tester from another mag said to me, ‘keep your weight well forward’.

Pretty common-sense advice for riders of modern dirt bikes I thought, as I looked up into a pale, terrified face complete with dinner-plate eyes. The 520EXC had obviously won that battle.

There was some awesome grunt there – you could short shift and use the torque to get around the thumper tracks at Picton easily. The 520 EXC doesn’t have the hard hit of power that I was expecting but strong power all the way through, although the bike we tested felt a little choked off the bottom. It was brand new though, (and totally stock) and could have done with a little mechanical fettling.

The power delivery through the mid-range and into the top-end is a little deceiving, as you can be going a lot faster than you think. The 520EXC would suit a better rider with strong technique, with that much power in a lightweight chassis things could get messy for the inexperienced. As with the 400 the handling is superb, picking up ruts and off camber turns are easy as it is so light and balanced.

The new bikes should be here early in the new year and should sell quickly – and as KTM is only building the new our-strokes in very limited numbers for 2000, be quick. Priced at $10,395 and $10,795 for the 400 and 520EXC respectively, Cycle Torque expects these to sell very quickly. The SX models will be $400 cheaper.