Engine

Choose your weapon, a 450 or a 525? We liked the 450 for tight woods racing and the 525 for long open fields. Either way KTM delivers an engine made for their high performance ATV. In other words this is not a dirt bike motor fabricated to work in a quad frame.

Before we let our rider Lance Schwartz tell you his thoughts on the powerplant, let's take a closer look at what's under the hood.

This is no ordinary engine borrowed from one of their dirt bikes. KTM started fresh and built this engine specifically for the abuse a high performance ATV can dish out.

Actually two versions of the same engine are available, a 450 and a 525. The difference between the 450 and the 525XC is the cylinder. Both include a single overhead cam four valve liquid cooled engine with an 11:1 compression ratio. The 450 is 448cc with an 89mm bore and a 72mm stroke, while the 525 is actually 510cc with a 95mm bore and a 72mm stroke. As you can see only the bore is different so parts can easily be swapped to fit one another. In fact both engines will fit into the same XC frame with nothing additional needed whatsoever. The well thought out design provides easy access for valve adjustment and inspection, and you can swap out a spark plug without removing anything from the quad. Maintenance on this quad should be extremely easy!

With no frame braces, beams or gussets in the way, the Chromoly steel frame allows plenty of room for maintenance and quick pit stop access. Not to mention it should be easy to wash.

It comes with electric start, which starts in any gear, and uses a five speed tranny with its reverse gear located below first gear.

The clutch system is very impressive and expensive. It uses a Magura hydraulic clutch with a stainless steel braided clutch line and comes complete with a quick change clutch cover. The end result is a maintenance-free clutch with automatic adjustment and effortless pull. Hat's off to KTM for this!

Lubricating the powerplant is just as well thought out. An optimized dry sump design offers increased oil capacity for ATV use and utilizes two oil filters, two oil strainers and a magnet all located in an easy access spot. Since there's no external oil tank there's less clutter, less weight and a lower center of gravity. KTM also uses 100% synthetic oil, another sign that they imply nothing but race-winning performance right from the start.

To make sure there would never be a cooling issue even in the muddiest conditions, KTM went the extra mile when they designed their ultra lightweight curved aluminum radiator. Its unique curved shape helps improve air flow for optimum cooling. The curved shape combined with its well designed mud louvers completely guard the radiator fins from loading up with mud from other rider's roost. "After extensive testing in Southern United States we've proved that this design won't allow any overheating issues. It's the best radiator and design I've ever seen," boasts KTM's John Maley. The radiator is fitted with an electric cooling fan and a thermostat helps maintain constant engine temperature. The fan worked so well the grass under the machine blew over when it fired up.

Here you can see the quick change clutch cover, high-flow header pipe and impressive rear brake pedal. All are high quality products usually associated with high dollar aftermarket purchases.

While other manufacturers are eagerly switching to fuel injection, KTM opted to go the old school route and sips fuel via carburetor. While we're not completely sold on their explanation of using proven technology obtained from the eighties and nineties, we are impressed with the actual carburetor they chose for the job and how they attached it to their design. "Besides cutting weight from the machine, KTM wanted to stick to the basics of race proven technology and stay clear of high tech computer systems, electric fuel pumps and relays." says KTM's John Maley about the decision to not use a fuel injected system. The XC quads use a Keihin FCR-MX 39mm flat slide with acceleration pump and TPS. No skimping going on here. This is a high dollar ultra-responsive carb and indeed top of the line.

The new KTM may be the most waterproof carbureted ATV ever.

Speaking of sucking air, a nifty high flow airbox design, as mentioned early by Lance, is used and we must say we're pretty impressed with the ingenuity KTM used here. Air is drawn from the highest point on the machine to help reduce the chance of bringing water and mud into the box. Getting to the air box couldn't be easier as no tools are required to remove the seat or the filter. In addition, the entire air intake system can be left attached when removing the rear fenders.

KTM says you wont need to replace the stock exhaust system. Hopefully KTM can start a trend and change many rider's opinion that loud equates to fast.

Exhaling air is done with just as much attention to detail as its inhaling procedure. KTM fits the quad with a high-flow performance-tuned header pipe and a trick aluminum silencer with a USFS spark arrestor. What's more is the exhaust emissions meet the California Green Sticker standard and barks at a mere 94 dB. Even though KTM sells an impressive upgrade exhaust system for the XC in their new Hard Equipment catalog, they swear you wont need an aftermarket exhaust system to win races. In fact, they're out to prove that a strong running thumper doesn't necessarily need to be loud and obnoxious to win on the track. "We have proven through endless hours of testing and dyno runs that we can indeed deliver the amount of torque and engine horsepower needed to compete in today's most popular race events with this stock exhaust system. It doesn't need to be loud to work well," explains KTM's John Maley. To continue on this "loud doesn't always mean fast" issue, Tim Farr recently raced the Snowshoe GNCC, where he finished 's 7th in the Pro Am class using KTM's aftermarket exhaust system (more details on this exhaust later), which is also quieter than most exhaust systems found in today's race quads. After the race, fellow competitors labeled his shiny new orange KTM "The KTM Stealth Bomber", after he silently slipped passed riders during the race.

Lastly, most ATV Scene.com staff members are also the personnel and promotional team behind the Maxxis 12 Hours of ATV America event, so we're especially pleased to report that KTM was crafty enough to include a stator worthy of 200 watts, so fitting high powered aftermarket lights to the XC KTM wont be so difficult and costly. Way to think beyond the GNCC box KTM!

"Both the 450 and 525 engines are absolutely phenomenal," says our Lance Schwartz. "The power they make is electric-like with torque from the bottom to the top of the RPM range," He adds, "I actually preferred the 450's tamer engine to the 525 for tight woods racing. The hydraulic clutch is also an excellent compliment to this machine."

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