Test Report: 1999 MXZ-670HO

Nov. 01, 2005 By Mark Austin

Well?to tell you the truth, I was kind of hesitant to write this test report on the grounds that the 670HO isn't being manufactured anymore and was replaced by the new MXZ-700. But the Snowmobile Online editors convinced me that it would be a worthwhile endeavor as there are still some leftovers from last year and there will always be a few used ones floating around. By some folks standards, the 1999 670HO was one of the best sleds Ski-doo ever made. By others, it was the last hoorah for an old dinosaur--nothing like going out with a bang!

Although the MXZ 670HO was only a "one year wonder", it sure did give a lot of other folks (and manufacturers) a wake-up call. With a basic Rotax 670 engine tweaked to the max, Ski-doo breathed new life into an old war-horse. Horsepower went up considerably over the previous year's model and the HO quickly became a dominating factor on the grass drag circuit. Pull it out onto a frozen lake and almost magically, other brands of 700 class sleds would come out of the woodwork looking for a bit of competition and to see if the new HO was really all that it was cracked up to be. They quickly found out that it was.

When I picked up my new HO, it had the same familiar feel as my old MXZ-583 (which I liked). The new sled sat in my garage for a few months and picked up a few extra goodies while it waited for snow. A pair of USI tunnel-light ski's, and a Dyno-Port silencer managed to find their way onto the new iron, as well as 192 Woody's 1.075's with angled backers and a hundred coats of wax.

Being used to riding a 583, the power of the HO was almost mind bending. I just wasn't used to hitting the throttle while doing 40 + miles per hour and then being up near the triple digits in what seemed like a second or two. (I knew immediately that I was going to like this sled). The low end grunt of this machine was a dream come true. If it hooked-up well, you'd better be hanging on tight. I also found out immediately that the throttle pull and the amount of reach, (the amount that I had to reach just to get my thumb onto it), was a real killer. By the end of the first day my thumb was really sore. It was very uncomfortable to trail ride all day with your thumb stuck out in a near 90 degree position. I really missed my dual stage throttle on the old 583. But like anything else, time heals all wounds and I quickly became accustomed to the new trigger. Fuel consumption was just as bad or worse than my old MXZ and came in at about 9 mpg. Oil consumption was typical for Ski-doo, using a lot less than the other sleds in our group. The stock clutching was spot-on and didn't leave much room for improvement other than occasionally adjusting the clickers on the TRA clutch for given conditions.

Grass Dragging The Summer Away

The SC-10 skid underneath begged to be ridden hard. At slower speeds it could be downright uncomfortable. This sled (or any of the MXZ line) is defiantly not for the Sunday driver. At higher speeds the HO skipped across bumps and moguls like they weren't even there.

After the first weekend's ride, I installed the AD Boivin ETS kit from my old ride and went back up north for another round. This definitely made a difference in ride quality at lower speeds but I do believe that the ETS kit may cut down on weight transfer somewhat. Nevertheless, I recommend it.

Handling was good but inside ski-lift was still very present even though Ski-Doo claimed that the newer "Advanced DSA" would help keep it to a minimum. Most Ski-Doo riders seem to get used to this fact and just deal with it. Once you know how the sled handles in the corners you don't even notice it.

The big difference in the new 670HO was the DPM (Digital Performance Management System). The DPM kept the jetting spot-on in all weather conditions. You never had to worry about running rich in warmer temps or lean in colder ones. This was really great when you wanted to race your buds when the temps started climbing and they were running fat. (I don't think they ever caught on). The DPM system works by reading temperature and barometric pressure. Unlike the complicated EFI systems, the DPM basically achieves the same results by simply putting a positive pressure or pulling a negative pressure on the carburetor float bowl. This in turn enriches or leans out the mixture. If the DPM should fail for any reason, the big 44mm Mikuni's would simply revert back to "normal" operation; that is, they would act like any other sled with carbs and no DPM.

Fit and finish was good and the footrests were at a comfortable angle. Some folks complain about the "sticky" seat on the Ski-Doos'?but I prefer it. (Come to think of it, the only ones complaining about it are the guys from those sled magazines. I've never heard a complaint out in the real world). I like my butt planted firmly when I ride and I like the sense of security it offers when blasting through tight corners. New for '99 on the 670HO was the addition of the "DESS" (Digital Encoded Security System). This was a nice feature and eliminates the need for a key. The tether has a chip installed inside of it that corresponds with the one on the sled. Without the proper tether, the sled won't run. A dealer can plug in his handheld computer and get information such as owner's name & address, hours on the machine, etc. This makes it very difficult for the bad guys to have a stolen sled re-programmed.

Due to poor snow conditions, I was only able to put 600 miles on the MXZ the first season. The only problem I had was knocking off a rear idler after sailing over a good size jump. In the summer/fall, I ran the same sled on the grass drag circuit in my area. Again, I had no problems.

For someone in the market for a used sled or possibly a left over from 1999, I wouldn't hesitate to recommend the MXZ-670HO. The only improvement I wish Ski-doo would make (on all models) would be to increase the running clearance between the track and tunnel/bulkhead.

If you would like more info. On this sled, feel free to contact me via E-mail.

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