KTM 200EXC

I don't mean to teach you to suck eggs (surely only perverts do that?) but if you haven't already noticed it, strange things are happening to dirt bike engines.

Only a few years ago, if you wanted to go fast you bought a big bike with a big engine. Big was important. "There's no substitute for cubes," the old farts cried, especially American old farts, and in the old days they were probably right. But nowadays - and if you don't believe me, go ride a YZ250F - for most of us, big engines are no guarantee of outright speed.

To our amazement, and despite what our hormones scream at us, a lot of dirt riders have found that they're faster through the bush on bikes with smaller engines. How can this be?

Two reasons: 1) a lot of people realised that hog-stomping grunt didn't necessarily make them faster. In a lot of cases it made them slower because big, fast bikes are physically exhausting. 2) the new generation of mid-size four-stroke engines have produced bikes that are easier to ride fast.

And therein lies the golden atom of truth. Way down deep, in the pit of our stomachs where all the righteous gut instincts live, is a devlish voice that whispers to us: "Do it harder, you big girl. Faster! Faster!

As it turns out, for most dirt riders it's a lot easier to go faster on a bike that's light, manoeuvrable and easy to handle than it is on barge that weighs 150kg and handles like a sloth on methadone.

This engine downsizing hasn't affected two-strokes as much as four-strokes - most of the innovation is going into thumpers right now, for a variety of reasons - but we still have horny little missiles like the KTM 200EXC to remind us what a two-stroke can do for those righteous gut instincts.

With just a fraction of a cube more, KTM has converted its punchy 125cc machine into a bike that's capable of surprising even the most experienced racers. This KTM is light, highly manoeuvrable, flicky, and seriously fast. That's if you're a good rider. If you're not a good rider it's light, highly manoeuvrable, flicky, and fast enough to be seriously frightening. It has more grunt than a 125 and almost as much as a 250. That makes it a fiendish grasstrack racer - get 'em under brakes and then dive under 'em - and more than hard to catch in the tight stuff.

It's not an 'experts only' proposition but if you're a decent rider you'll get a lot more out of this thing than if you puddle around off-the-pipe. In that respect the KTM 200EXC is much like a chainsaw: at idle it does nothing but at full noise, shee-yit! - all hell breaks loose.

The 200 is more a race bike than a trail bike but if you're a hard punter and you enjoy two-stroke power, you'll love this thing. Mind you, it can take some getting used to, as we discovered when we hooked up with former national enduro champ Tony Vickers for a photo session and a few technical tips. 'Bones' had started racing again, and on a 200EXC: "I'd just come off a 400 four-stroke back then so I wasn't really prepared for the kind of power this 200 puts out. The KTM can be savage, it hits real hard, believe me, in fact a few days before my first event I was still wondering how the hell I was going to race the bloody thing. I had to get on it every day just to get used to it, even with my 125 experience, but now I'm used to it I reckon the 200 is a real buzz to ride."

"Buzz" is doubtless an appropriate word if you ride like Tony Vickers; shit-faced fear is probably closer to the mark if you've never had to hang on to the handlebars with all your strength, for the simple reason that if you don't, you will be sucked off the back of the bike and fed to the rear wheel in small fleshy parcels.

FAST FROM ANY ANGLE
The 200EXC has changed somewhat since its introduction in 1998 and that's a good thing. It's front-end is more stable, it exhibits less headshake than it did and the engine now claims a stronger midrange and top-end. The bike also looks narrower through the centre, though that may be an optical illusion brought on by the flattened eyeballs.

Some things could still be improved though: the brakes would certainly benefit from a more progressive action, more power and better feel. The standard front brake is also a bit grabby. Tony Vickers removed the stock Brembo discs and replaced them with thicker Gold Fren "wave" discs from the Czechoslovakian Republic (of all places). The new setup gives stronger brakes with the stock brake pads, though Tony says the brakes would be further improved with softer pads, which won't last as long but will generate more braking power and run cooler.

The KTM engine also detonates furiously, even on Premium Unleaded, and the problem can't be cured with jetting. Tony fixed it by getting his Dad Ray to match the transfer and exhaust ports to the piston, then take about 0.5mm off the top of the piston to reduce the compression ratio. This had the effect of smoothing out the power delivery, improved the top-end slightly and made the bike less of a handful in slippery conditions where traction comes and goes like that Arab in the Corolla.

Jetting changes were made too. As you'd expect, the KTM arrived with lean brass. Tony fitted a 45 pilot jet, a 178 main in place of the 170 stocker, and a NOZG-series needle, positioned in the second clip from the top.

"This combination works well with Motorex CrossPower 2T premix at 40:1," he says. "The power's fine and we haven't fouled a plug yet." (As a matter of interest to 200EXC owners, the NOZF needle in the spares kit smooths out the power delivery more than the G-series needle. Try it; you might like it.)

The KTM200 is sold with 48-14 sprockets, which aids the lively acceleration but gets you into top gear pretty quickly. Unless you ride in a Harvey Norman showroom, that gearing is too low to live with. With 48-14 gearing the 200 will actually pull holeshots in third gear!

Tony says a better proposition is 47 or even 46-14: "This gives the average trail rider higher cruising speeds, which is important when you're riding big fast fire trails or getting home after a day in the bush. With this slightly taller gearing the engine won't light up as hard in second gear, either.

Personally, I reckon 46-14 represents a pretty sound compromise for most trail riders.