June 4, 2007 – Six years in the making

It’s official — times have never been better for consumers in the market for a sport quad.
Can-Am recently took the wraps off its new DS 450, a groundbreaking 450cc sport quad that joins the Yamaha YFZ450, Honda TRX450R, Suzuki LT-R450 and the recently released Kawasaki KFX450R in the ultra-competitive, high-performance sport quad segment.
Under development for six years, originally as a competition two-stroke, Can-Am has produced a striking four-stroke machine with innovative features. For starters, Can-Am says the DS 450 has the most power in its class, the lowest dry weight, most centralized mass, lowest unsprung weight and the industry’s first all-aluminum, nonwelded chassis.
Del Bohlman, Can-Am’s product, media relation and racing manager, says the project originally began in 2001 as a two-stroke quad.
“We had the DS 650, but we wanted to get into another segment in the sport ATV market,” he said. “At the time, the two-stroke was still dominating the race tracks and we felt we could capitalize on the success the [Honda] 250R saw in its — at the time —15-year reign in the sport market.”
Bohlman adds that as the project progressed, it was clear four-strokes were taking over the market and the quad needed to be reconfigured with a different engine.
That engine, a 449cc Rotax 4-Tec with EFI, has family ties to the Rotax V990 “Mille,” which powers the Aprillia RSV 1000 R sport bike. However, the crankcase, clutch and transmission were redesigned for use in the off-road ATV. The industry’s largest piston bore (97mm), intake vales (38mm) and throttle body (46mm) contribute to the machine’s aggressive nature and high-flow design. Dual spark plugs are also a 450-class first. Can-Am says its tests have proven the 4-Tec mill offers 9 percent more engine power (hp at rear axle) than its best-in-class competitor, the Honda TRX450R.
No-Weld Frame
The DS 450’s ALTEC frame was designed with assistance from Alcoa, a world leader in the aluminum industry. It’s 13 percent lighter than anything in its class and is constructed of aerospace-grade aluminum in a dual pyramidal design, similar to the Ski-Doo REV snowmobile. Can-Am says this configuration lowers the frame’s weight, improves vehicle control and reduces rider fatigue. The pyramidal setup means fewer materials are required to make a strong structure.
Can-Am’s engineering team found a way to offer an aluminum chassis that’s the lightest in the industry by using Finite Element Analysis (FEA), a no-weld design and aluminum lock-bolts. FEA shows stress points and determines how thick or thin a certain piece should be. The object was to create a balanced chassis for durability and weight savings.
“This enabled our engineers to see what points needed to be reinforced while the frame was still in the design process,” Bohlman said. “It is all done on the computer before we even build and test the prototypes.”
Since the DS 450 frame has no welds, it’s able to keep additional weight off, resulting in the lightest weight chassis in the industry, according to Can-Am’s calculations.
Found in the Airbus A380’s 199-foot wings, lock-bolts are a two-piece assembly and are much lighter than the traditional steel bolt and nut combo. A lock-bolt is actually a fastener that is permanently clamped to an area and resistant to loosening. The “bolt” segment is inserted in the chassis, stretched, secured with the “nut” portion and then squeezed tight and excess material is cut off. The lock-bolts don’t have threads, which means they can’t back out or vibrate loose.
Lightweight Components
To reduce the DS 450’s unsprung weight, which Can-Am defines as “the weight of all components that follow the wheel travel,” engineers added both upper and lower forged aluminum A-arms. Also, the DS 450’s inverted brake caliper and peripheral Wilwood disc brake design allowed space for the industry’s largest stock A-arm width (16.5 inches). It also meant the ball-joints and kingpin axis could be placed inside the wheel, the only such design in the sport quad field.
Aluminum-bodied Kayaba HPG piggyback shocks, with 9.5 inches of travel, are adjustable for compression, rebound and have a threaded preload adjustment.
Weight was shaved from the rear with a hollow axle, which Can-Am says does not reduce strength. Extended-reach aluminum axle hubs, sprocket hub, disc brake hub and a cast aluminum swingarm also contribute to the lighter weight. The company says because of the DS 450’s reduced unsprung weight, the rear wheels stay in contact with the ground more and provide improved traction. A single aluminum-bodied Kayaba HPG shock, with 10.2 inches of travel, suspends the rear end.
It all adds up to a machine that weighs 345 pounds dry — 5 pounds less than its next-lightest competitor, Yamaha’s YFZ450.
Awaiting Availability
Can-Am says its DS 450 will begin arriving at dealerships near the end of summer, with a gradual introduction into the racing world.
Jeremy Schell and Josh Frederick are set to race the DS 450 in the WORCS races and ITP Quadcross races out West sometime this year.
“Like any new machine, there will be a bit of dialing in to do before we start in earnest with our DS 450 program,” Bohlman said.
While the new 450 was being introduced, plans were announced to discontinue the aging DS 650 from the Can-Am sport quad lineup. Bohlman says although it had its benefits, like being the fastest and most powerful sport quad on the market, it was showing its age compared to the rest of the company’s sport models.
As for any plans to replace it, Bohlman said, “I guess you’ll just have to wait and see.” psb

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