2000 KTM 520SXFThe 2000 KTM 520SX four-stroke pre-pro was tested in the December 1999 issue of MXA.

The market for full-bore, full-blown, full-size, full-race four-strokes has always been fairly limited. Most of us would love to own a monster thumper, but only if we won the lottery (and after we bought a standard-issue YZ, CR, KX, RM or SX). Truth be told, big bore four-strokes have been a hard sell. Very few riders can justify spending megabucks on a bike that they have no heritage with, understanding of or appreciation for. No big surprise there!

Or, at least the anti-four-stroke sentiment was no big surprise until Yamaha introduced the phenomenal YZ400. When Yamaha resurrected the four-stroke from the dinosaur category it breathed new life into a style of power and way of riding that has been forgotten in the gun-and-run era of clutch-happy wrist rockets.

The YZ400 was a hit, and not just a studio hit, it played big all across the air waves. In fact, Yamaha sold as many YZ400s as it did YZ250’s–that’s no small potatoes considering Yamaha’s runaway success of the last three years.


What is a surprise is how far afield the Big Four (that is the four that remain after counting Yamaha) stayed from what was obviously a lucrative piece of the pie. Honda, Suzuki, Kawasaki and KTM seemed to be afraid of the YZ400. So scared that Honda and Suzuki chose to take a different tack with their new thumpers (DRZ400 and XR650R),Kawasaki played see no evil and KTM, to their credit, decided to go racing before going into production.

At least KTM was willing to follow the YZ400’s lead. It’s a strange world that has a European manufacturer being the only brand enough to buck the YZ400.

The KTM 520SX was built to compete against the Yamaha YZ400. 

Late in 1998, KTM announced that they would drop kick their old line of four-strokes, first penned in 1982, an attack Yamaha on its own playing field (they meant the 500 World Championships). True to their word, KTM entered a prototype KTM 520SX in the 1999 World chase and acquitted themselves honorably. Swedish rider Peter Johansson, who had been the test rider for the Yamaha YZM400, signed on to race the 520SX. When he didn’t break, the Swede won!

As KTM bask in Grand Prix glory, they also announced an ambitious four-stroke program for the 2000 model year. Not only would they produce 520cc and 400cc versions of Peter Johansson’s race bike (designated SX-models), but they would also offer bikes with the old engine (which they labeled venerable), enduro models, cross-country models and electric start models.

This is where the MXA wrecking crew entered the picture.


“We have an idea,” said KTM’s Scot Harden one day at Glen Helen. “If MXA would be willing to go to Europe for the Dutch 500 GP we could arrange for you to meet with the team, go to the factory and ride the first 2000 KTM 520SX. What do you say?”

“No,” we said. Harden was shocked. “We were just in Holland for the 250 Grand Prix, we recently came back from Brazil, we’re tired of traveling and, anyway, we don’t test bikes outside of our known circle of test tracks. It’s not that we wouldn’t like to go, but it would be a waste of time and money. We will only test the 520SX if you fly it to us.”

2000 KTM 520SXF action
test riders loved riding the bike. 

“Okay,” said Harden. “We can do that. The bike is in pre-production form right now, but I think we can have it flown in by next week.”

“No,” we said. “We don’t test pre-pro’s. We only test production bikes. The only way we would even consider riding a bike that wasn’t in production is if it was at least four months away from the assembly line and we were the only ones to ride it.”

“No problem,” said Scot Harden. “The 520SX and 400SX will not go on the assembly line for several months. The factory has made a small run of pre-production bikes to test the components, work out the bugs in the assembly line and for the race teams in different countries to test. The bike we give to MXA will be one of those pre-pro race bikes. It’s a chance to be the first to ride a bike that no one else will see for months.”


The MXA wrecking crew first threw a leg over the KTM 520SX during the first week of September. It was an impressive bike. But, we want to make clear that it is a pre-pro. What is a pre-pro? The process of building a new model requires four major stages: (1) Blueprints. (2) Prototype. (3) Pre-production. (4) Production. The pre-pro stage is when the last-minute bugs are worked out of the machinery before it is cleared for mass production. The bike that KTM handed us at Glen Helen was a pre-pro. It had flaws. We found them. But it was still a provocative piece of equipment.


The most significant technical aspect of the 2000 KTM 520SX is that it isn’t a Husaberg rip-off. It’s no secret that KTM owns Husaberg and borrowed heavily from the Swedish manufacturer during the early stages of R&D on the 520SX. They borrowed so heavily that many prototype and pre-pro bikes used Husaberg top-end components. Not so on the bike that KTM uncrated at Glen Helen Raceway. It was all KTM (okay the clutch is still a Husaberg item, but if KTM knows what they are doing they will change it before production).

2000 KTM 520SXF
This engine wasn’t borrowed technology from Husaberg. It was built by KTM. 

The second most significant technical aspect of the 520SX was its claimed weight. KTM told us that it weighed 229 on their shipping scale. We laughed at them. Not only did we guffaw out loud, but we took the bike to MXA’s personal weights and measurement department and weighed it side-by-side with a Yamaha YZ400. The result? Yamaha–251 pounds. KTM–236.5 pounds. We were impressed. That is light (and if it stays that light until it hits the showrooms KTM will have achieved something big).

The third most significant technical aspect of the 520 is that it is fast and smooth. More accurately, it is smooth and fast. When the YZ400 was first released every test rider marveled at the automobile-like powerband of the YZ400. It had little in common with the chugging, throaty, torquey four-strokes of old. The YZ400 purred like a kitten and roared like a lion. It was clean down low and revved to an astounding 11,200 rpm. The YZ400 engine was the first four-stroke motocross engine with a Formula One background. Forget all about that, the KTM 520SX is smoother, more car-like, broader, easier-to-ride and more powerful (which its’ extra 120cc’s almost insured). It is a sparkling presentation of power output. Silky, but sultry.

The fourth most significant aspect of the SX is the engineering. It’s obvious that KTM took a long look at what had been done in the past and tried to improve on it. Take, for example, the dual oil pump lubrication system. One oil pump draws oil from the gearbox through two filters (one paper and one metal) to the top-end. The second oil pump returns oil from the crankcase to the transmission. All of the oil lines, save one, are integrated into the center cases. There are a total of seven integrated lines. Why build them into the cases? Because they can’t be damaged, ripped off or spring a leak (plus the external oil lines on a YZ400 add over one pound to the engine’s weight).

2000 KTM 520SX dual oil pump lubrication system

The fifth most significant technical aspect of the KTM is that it isn’t jingoistic. KTM isn’t too proud to spec the best parts — even if they come from Japan. Thus, you will recognize the 39mm, slant-body, Keihin FCR carburetor. It’s off of the Yamaha YZ400 (although the Yamaha YZ426 has a new straight-body Keihin). Additionally, the ignition is a Kokusan 4K3 electronic unit which not only controls spark, but also meters the Throttle Position Sensor (TPS) on the carb. The third Japanese product on the Austrian bike is the Bridgestone rubber. The 520SX comes with M77/M78 sneakers.

The sixth most significant technical aspect of the KTM 520SX was that they wedged it into an almost standard-issue KTM 250SX chassis. It should be noted that “almost” is the operative word. One tube had to be raised above the frame, the split-cradle had to be adapted for the four-stroke engine and the complete lower section of the chassis was lowered to allow room for the engine. The frame geometry does correspond precisely to the KTM two-strokes.


We offer kudos to KTM on these points: (1) The engine is great. (2) The powerband is great. (3) Starting is great (thanks to an automatic compression release). (4) The horsepower is great. But, in pre-pro form the bike needs a little work (which KTM promised that it will get). We whined that the kickstarter stuck down, that we couldn’t find neutral, that there were two clicks to first gear (the 520SX has a four-speed tranny), that the bike was geared too tall in first, but not tall enough in fourth, that the clutch couldn’t take much abuse, that the rear suspension could use better damping and that the bike seemed to run a little hot.

2000 KTM 520SXF engine

The best thing about getting MXA to test the pre-pro is that we can’t really complain about any of the flaws we have listed above. We can guess that the 520SX will cost about $400 more than a YZ426, but we can’t say for sure. We can worry about the clutch, over heating, vague neutral, balky kickstarter and odd damping — but since none of it has been finalized for production we can only say that KTM promised to fix the things we complained about. It’s the Catch-22 of test riders. A bike that really can’t have a donkey tail or Medal of Honor pinned on it — at least not yet.

Will they fix the flaws? We’ll let you know in a couple of months when we test the real thing.


We think that Yamaha will have it’s hands full. Shame on Honda, Kawasaki and Suzuki for running scared (or for believing that it would be a wiser business decision to go after the trail bike market). What KTM has achieved proves that the YZ400 isn’t unbeatable. Without the might, money and resources of the Japanese manufacturers, the Austrians have established that a little chutzpah goes a long way. It’s amusing that it was the smallest, least financed and most under-appreciated of the Big Five manufacturers that set out to prove that the YZ400 could be bested. If it’s true, the Big Four will have to get their R&D departments into overdrive.



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