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,. I Can-Am III • ~ t 10 r-.. O'l !"""'l By John Huet1er 250'5: MX-2 and TN'T Have we been spoiled in one short year? 00 C'J l-o Il) ..0 0 ..... u . 0 The Can-Am 250s should have been the Great (North )American Motorcycle . The disappointment comes with a re ally saddening wrench when you discover they're not. They are certainly quite American, for Austro-Canadian creations, in keeping with the American automotive tradition of machinery heavy on the horsepower with poor to indifferent handling. The Can-Am 250 MX-2 motocross model is all that you might have heard it is in the pony production department. You migh t also have heard that sheer horsepower alone does not win dirt races. Even Kenny Roberts probably believes that, by now. The 250 Can-Ams appear quite similar in their basics, excepting the obvious differences like ligh ting equipment on the enduro. Performance differences stem from the enduro 's large canister exhaust (while low in cBa scaling, the audible "ping" is annoying to bystanders) rear suspension, and standard tires and rims. That doesn't sound like much but the result expressed in handling and ride are significant. Both machines share similar frames. The rearmost downgusset on the is further forward to MX-2 accommodate dampers moun ted 6.75 inches ahead of the axle. Wheelbase of 54 inches is a little short compared to most competition chassis these days. (A Bultaco Pursang measures 56, for example, and a KTM, 57 . Neither suffer in cornering.) Both Can-Am models can have the effective fork rake altered in half degree increments from 26.5 to 31 degrees by changing eccen trics in the head. Th e frame and suspension location allow 4.75 inches of rear axle travel on the enduro and a hair over six on the Unfortunately, the front MX-2. suspension travel on both is also a n ominal six inches. Even though the travel is provided by Betor forks, six inches is just not competitive in either the current enduro or, .especially, motocross scene. And to further erode a cherished myth , the action of these obsolescent Betor forks was not very impressive. (You know where all the excellent eight-inch Betor forks are. On the front of machines whose names end in vowels and are built in Spain.) On the TN'T, the front springs were sagging with 53 miles showing on the odometer. This reduced effective travel on compression to about four inches. One result was that they bottomed through holes that we hadn't been accustomed to bottoming through in some time, at least since suspensions On the fast TT·type tracks of Southern California, the MX-2's J-curve power comes into its own. Witness the recent successes of Ron Turner (lx) in CMC racing, or of the infamous Jorgy's Can·Am in District 36. • have improved radically. The MX-2 measured nearly 6.5 inches of travel with what appeared to be fluid of 20 wt, viscosity in its Betor fork. And it used all the travel, both topping and bottoming in a fashion that turned even mild down hills in to white knuckle rides . Draining, cleaning, and refilling of the forks with 40 wt, fork oil improved the action significantly while reducing travel to 5.5 inches. It was a disconcerting thing to encounter Betor front suspension that was less than excellent. What this lack means to the rider is that in cornering, most of the available fork travel gets used up in the process of braking and weigh t transfer and there just isn 't enough left to handle any bumps on the ground. Rider confidence in cornering suffers severly, With the fork compressed this much, and a stock fork rake of 30 degrees the front end wants to slide right on out from under you, and will if you don't get a foot planted quickly and firmly and pull it back. On the enduro, the front Cheng Shin trials tire would seem to lift off the ground a hair as it went to the outside. On the MX-2, the front Yokohama 900 knobby would just slide out. The 54-inch wheelbase does not seem to help in getting around turns nor does the frame design, which leaves the word "uncertain" in your mind when it comes time to describe it . At th e rear of the MX-2, we tried 10D-lb. springs slipp ed rather loosely over aluminum body KONls. (StandlZrd shocks are made-in Mexico S & Ws). This did not keep the rear end from bottoming over m edium-size jumps but did overcome the KONI rebound damping to fling it back in a bouncy, disconcerting way. There are, however, five different sprin g rate options from which to choose at the time you purchase a Can·Am. Aluminum KONls can be made to work for longer than 15 minutes around a motocross course. Possibly because they're ouersprung (Though 100 lbslin would seem about right, in theory.], the ones on the Can-Am didn't. Another cherished myth about the universal suitability of the latest KONI damper was shot down. . . . . Ed. The S & W shock absorbers used in a less stressed manner at the rear of the TN'T perform their job relatively better but then it's an easier job. They still don't work as well as they need to for fast cross-country work in the 35-50 mph range. Horsepower is what Bombardier is using to sell the Can -Ams. But in the real world, peak dyno horsepower re adings do not tell the story of how well a machine is suited to its intended purpose. The heart of both Can-Ams is the Austrian-built Rotax rotary valve engine, carbureted by a 32mm Bing positioned at the end of an engineered in take tract behind and below the cylinder. There is no doubt that a rotary-valve 250 engine can be designed to produce a lot of power. It's a shame that they didn't see fit to use a rotary disc that would spread the power delivery over a broader RPM range. The delivery of horsepower from the MX-2's engine seems to follow a J-curve: very flat at low RPM, then peaking quickly to a maximum. The feel is further accentuated in riding by a progressive Magura throttle better suited to a power of the ' exact opposite curve configuartion. A 250 motocrosser with five or six fewer peak horsepower will consistently beat the MX-2 out of a comer. Only if the straight to the next tum is lo ng enough will the Can-Am catch it. When the right RPM number is reached, the power climbs immediately. So fast, it will pitch the MX-2 sideways