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KTM ATV 525XC & 450XC Sport ATV - Race Ready

2008 KTM 525XC & 450XC ATV Press Intro - Test Ride

Walsh Race Craft custom built ATV with a Chromoly Chassis & KTM 525 Engine
Walsh Race Craft custom built ATV with a Chromoly Chassis & KTM 525 Engine
The first order of business for KTM was to pull a proven engine configuration from their vast array of bike engines and fine tune it for the unique demands of the racing quad. They chose the 450cc and 525cc single overhead cam four valve engines that have delivered reliable performance in a number of racing bikes for over seven model years. The 525 is virtually same engine that Mike Walsh campaigned is his own chassis for a few years, winning the 2002 ProAm MX National Championship. More importantly, Mike used this engine to finish 2nd in the 2005 Pont de Vaux 12 Hour event, a grueling endurance motocross race that over the years has brought out the absolute performance envelope of almost every engine configuration in existence, and this was a motorcycle engine without the reliability modifications that were incorporated into the new XC quads.

The crankcases on the XC engine were reconfigured to hold almost two liters in the enlarged sump, eliminating the need for a reservoir tank, oil cooler, and potentially problematic oil lines. Both engines share the identical lower end, which utilizes a 72mm stroke crankshaft. The 450 and 525 top ends are interchangeable, and this adds considerably to the versatility of the machine if the owner wants to change racing classes or decides he needs more power for play riding.

2008 KTM 525XC & 450XC ATV  engine
2008 KTM 525XC & 450XC ATV  engine

The 450XC’s nikasil-coated cylinder has an 89mm bore, and the total displacement is 448cc. The 525XC engine displaces 510cc with a 95mm piston. Both engines run an 11:1 compression ratio. Two oil pumps handle the oil flow duties, and tandem oil filters keep the vital fluid fresh as long as possible. For ease of maintenance, the filters are conveniently located next to one another atop the transmission area of the cases. The 5-speed transmission with reverse is engaged by a multi-plate wet clutch that is hydraulically actuated, and easily serviceable through a quick-access clutch cover. The engines are brought to life with a powerful electric starter, and through extensive testing and tuning the starting has been made so reliable that the need for a kickstarter has been totally eliminated. Fast dead engine starts were a priority during the development of the quad, and we all know how important of a detail this is.

2008 KTM 525XC & 450XC ATV 39mm Keihin FCR Carburetor
39mm Keihin FCR Carburetor
In the era of the great fuel injection race, KTM has opted to use the proven and effective 39mm Keihin FCR carburetor on these quads. It is hard to argue the ease of tuneability and reliability of the FCR, and the TPS equipped carbs are readily available and easily serviceable. Both the choke and hot start are located on the carburetor, and time will tell if the hot start will be needed often or not during mid-race restarts.
2008 KTM 525XC & 450XC ATV unique air filter system 2008 KTM 525XC & 450XC ATV unique air filter system
KTM's Unique Air Filter System for added water protection

The air intake is an all-new design that is aimed at maximum waterproofing, while still allowing enough air flow to supply the engine. While most ATV intake tubes attach directly into the front of the airbox, the XC pulls its air through the top of the airbox lid where it is at the highest possible point to avoid watering out. The filter is the same foam Twin Air unit as those used on many of KTM dirt bikes, and it is such a common part it should be stocked by most shops. The whole process of changing the filter can be done in less than a minute, without the need for any tools. For race conditions that allow a more open airbox, a removable snorkel piece can be taken off for more airflow. If even more air is required, there are small ducts on the side of the air filter compartment that can be opened up for maximum airflow.

2008 KTM 525XC & 450XC ATV aluminum exhaust csnister
Aluminum Exhaust Canister
Handling the exhaust duties is a very clean looking stainless steel header and aluminum muffler. The 2 into 1 performance header is a work of art, with perfect welds and a tucked-in large diameter head pipe. The silencer design is derived from KTM’s four-stroke bike technology, with an aluminum canister and cast aluminum end cap. This lightweight yet strong design is California Green Sticker legal, and only emits 94db. The quads are very quiet, and with good performance and low noise it may be hard for riders to justify installing a race pipe. With more and more tracks and promoters requiring sound tests and noise restrictions, this makes for one less thing to worry about when going through tech inspection. KTM is offering a tuned Akrapovic full titanium system for those seeking maximum power. This factory Hard Equipment unit has removable muffler inserts, and still retains a spark arrester.

2008 KTM 525XC & 450XC ATV cooling system
The cooling system consists of a large curved aluminum radiator with an electric cooling fan. A thermostat helps to maintain constant engine temperature. No oil cooler is needed, eliminating problematic oil lines and fittings. The curved shape and advanced ducting designs keep airflow at a maximum.


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