1997 skidoo mx z 670

Early this season, American Snowmobiler reported that Ski-Doo'sMX Z 583 offered such a fine chassis and outstanding handling that it demanded more power. In a review of the Mach I (Jan./Feb. 1996) we commented that we would like to see the Mach's 669cc twin in the MX Z chassis. Apparently,Bombardier decided to call our bluff. Called to Mont. Valin, Quebec, justbefore Christmas, we got the opportunity to test ride the new MX Z 670.It was better than we expected. We had heard rumors of the hotter MX. Asthe introduction drew closer we found the rumor turning to fact. The bigquestion was what kind of exhaust system Bombardier would use. That questionwas answered in Quebec.

The MX Z 670 uses a slightly modified version of the 669cc twin foundin the Formula SS. This is the "detuned" version of the more expensiveMach I motor; the dual 40mm Mikuni carbs were recalibrated to specificallymatch the engine to a new two-into-one exhaust system. Everything else isstraight SS, including the rotary valve intake and mechanical Rotax AdjustableVariable Exhaust (R.A.V.E.). Internal porting is the same and the engineretains its 78mm by 70mm bore and stroke dimensions. You will note thatthe engine's operating rev range is limited at 7,600 to 7,800 rpm. Our estimatesput the engine's power in the 110-115 horsepower.

This sled has extremely good power and is well-suited to the chassisand suspension setup. Even after just a few miles, we found that the powerto weight ratio of this 502 pound, 100-ish horsepower sled was outstanding.Choosing between the Ski-Doo MX Z 670 and a Yamaha Vmax 600 XT with thetwin pipe GYT kit would be tough. In the Ski-Doo's favor is neck-torquingpower from low end to mid range. The exhaust system is specifically designedto augment the 670's already excellent characteristics in that range. Ski-Doochose the single pipe over the Mach's dual pipe setup because the dual pipesadd weight, and while the twin pipes would make the sled stronger at thetop end, the midrange and out-of-corner acceleration would be compromised.Count on aftermarket pipe builders to fill the void for you Ski-Doo MX Z670 customers who must have dual exhausts, but there won't be many of youlucky enough to get one. The limited build of 1,200 units translates toabout one per dealer.

We also like the fact that Ski-Doo incorporated the Acceleration andControl Modulator (ACM) coupling device in the latest production MX Z models.This simple, but effective coupler marries the action of the rear suspension'sfront and rear torque arms. A rider can readily dial in his choice of theholeshot acceleration or more ski bite for cornering. We also felt the systemresulted in a better overall translation of mogul-mashing response fromthe front arm to the rear. The SC-10 MX suspension communicates better,resulting in a more controlled ride.

The MX Z 670's rear suspension utilizes lightweight, chromoly constructionin conjunction with the high pressure gas shocks. The end result is a rearsuspension that provides up to 10 inches of travel. Of course, a bit ofthat is "sag," which is used up as soon as you sit on the sled.You will like the performance of the SC-10. It may be stiff for some, butfor go-fast mogul riders, it will be greatly appreciated.

Up front is the trailing arm unit seen on other MX models and provensuccessful by cross-country riders like Ski-Doo ace Toni Haikonen. The DSAfront delivers seven inches of travel and is controlled by HPG shocks. You'llfind narrow skis hung out on the 41 inch ski stance. Here you might checkout any of the aftermarket plastic options to both save a little extra weightand improve top end as well as floatation.

Everything that we liked about the MX Z 583 holds true for the MX Z 670.The side padding is a great idea. We enjoy the straight handlebars. We reallyappreciate the positive stopping power of the Bremo disk brake. And, you'llfind the nearly 10-gallon fuel tank to be to your liking. There is a priceto pay for the power and the 40mm carbs: the MX Z 670 will be more thirstythan the 583. But we can live with it.

In fact, we can easily live with the limited edition Ski-Doo MX Z 670.Bombardier is not just listening, but responding. And darn quickly!

1997 SKI-DOO MX Z 670

Engine: 669cc ROTAX® 670 liquid-cooled twin w/ Rotary valve, R.A.V.E.
 Exhaust: Tuned pipe to spiral muffler
Clutching
Drive: Cushion drive T.R.A.C., 3 ramps
Driven: Formula, cam, on countershaft
Suspension
Front: DSA; 7 inches
 Rear: SC-10 Cross-Country; 10.0 inches
Ski Stance: 41 inches
Overall Height: 44.1 inches
Overall Length: 107.3 inches
Fuel Capacity: 9.8 U.S. gallons
Offical Dry Weight: 502 lbs.
 Price:US  $6,999.00
Key Features: Carbide runners, front shock absorber kit (HPG), heatedgrips and throttle lever, hi-beam indicator, injection oil level indicator.(mechanical) fuel gauge.
Riding Impressions: Everything we said about the MX Z 583 holds truefor the MX Z 670 - and then some. The 583 screamed "more power."It got it, plus improved handling. But you better move, they won't be aroundlong.- Jerry Bassett, test rider