We had a brief ride on Arctic Cat’s new 800-powered ZR800 last week and came away impressed. The new engine is a mirror image of Cat’s 600DSI, slot-injected twin but has a couple of differences.
The engineers have used two “side valves” per cylinder the 600 doesn’t need and these valves, located inside two small ports on either side of the exhaust port allow the 800’s big pistons to pass by the humongous exhaust ports without hanging up the piston rings.
These ladies wristwatch-sized valves are mechanically operated and work in tandem with the electronic exhaust valves to open and close during the various cycles of the engine (intake compression, combustion & exhaust).
There’s also a valve located on the fuel rail that regulates the “flutter” in the rail and keeps both injectors working in sync.
Other than the fact this engine has more displacement, it appears to be dimensionally identical externally to the 600 and especially to the old Suzuki 800.
Riding this engine is a different story. Although we suspect the top end is about the same as the old 800 (not too shabby, really), bottom and mid-range are completely different.
This engine pulls with immediacy down low and snaps to attention whenever you get into the throttle off-idle.
Mountain riders are going to love the way this engine responds in powder when it looks like there’s a possibility of getting stuck. Just crack the flipper open and this mill responds with telepathic reflexes and gargantuan bottom end.
Same goes for the mid-range. On trails, this engine feels very muscular and when you dip into it at about 40-mph, it just lofts the skis and takes off with authority. The speedo keeps climbing smoothly and we observed no flat spots, burbles or hesitation anywhere in its power curve.
This new 800 is certainly much more civilized than the Suzook 800 and runs very much like the 600. We think it will prove to be a formidable foe to the Polaris 800 and maybe even Ski-Doo’s 850.
One thing is for sure, Cat 800 owners are going to see a big improvement here and will love this new powerplant!