AmSnow.com is now SnoWest.com
Despite the performance image and marketing, the invaders were fitted with a large 2-up, stepped “king and queen” seat in an era where many performance sleds were moving to a single “race inspired” seat. To drive home the performance, a ’78 Invader 340 grabbed a second place finish in the Winnipeg to St. Paul I-500 behind Brian Nelson’s winning El Tigre. Reloading to their motor supplier roots a year later, Kawi began supplying John Deere 340 and 440cc fan-cooled single carb motors for their new 1979 Trailfire before powering the entire “New Breed” lineup through 1984.
Invading complete
In the years following the Invader’s 1978 debut, the improvements kept coming. For 1980 the Invader performance was boosted with its “four-into-six” porting, four spark plugs and factory dual pipes in a machine now called the LTD 4/6. This basically added two small booster ports to the cylinder, so the T-7 engine geometry of four transfer ports was maintained, but they updated the cylinder wall to a total of six scavenging ports. While the estimated six to seven additional horsepower was nice, a larger radiator was added to help keep the more powerful 440 running cool. This larger radiator was laid down horizontally, requiring a large bulge added to the top right of the hood to help with airflow. Unfortunately, this disturbed the otherwise clean lines of the Invader hood. For more performance however, something else was going to be required.
From 1971 until 1980, Kawasaki had two families of piston-ported twin-cylinder snowmobile engines. The T-1 based motors were used in most of the ’71-’75 Cats. The slightly newer T-7 family of motors that debuted in the 1973 EXTs and El Tigres had a wider cylinder spacing, enabling larger transfer ports and more cooling fin area, giving the T-7 motors more performance potential over the T-1 design. For example, the ’71-’75 Panthers and ’79-’84 Trailfires were T-1 based. But the ’74 Sno Pro motors, Invader and Liquifire liquids along with the Intruder and Sportfire fans were T-7 based architecture.
To stay well-armed in the escalating horsepower wars for 1981, Kawasaki released an all new 440cc twin, called the “Square Block” featuring eight scavenging ports, a large rectangular one-piece head, four spark plugs, oil injection and significantly increased horsepower over the mid-70’s numbers of the 4/6. This new engine also had a significantly reduced part count over the T-7 based LC 440s.
The new eight-port 440 was only offered in the 1981 LTD, again with factory dual pipes and the larger cooling system. It had the bulging hood of the previous years 4/6 too. Electric start was an option, and the king / queen 2-up seat was standard. Kawi seemed to be marking the sled as the top of the line performance / 2-up / good as it gets machine. However, between the shrinking market and confusing positioning, it didn’t hit hard with consumers like the original Invader did. The original 440 Invader was still offered in ’81, along with the fan-cooled Intruder and budget-minded, deep-snow marketed Drifters, but there was room at the top for more. Starting in the late 70s, top of line performance sleds were starting to turn past 440cc LC twins. Polaris raised the bar with the big triple 500cc Centurion liquid in ’79. Then Cat hit back released the 500cc El Tigre in 1980, and gained the title of the “World’s Fastest” in ’81. While Kawi’s new eight-port 440 was a solid response to the escalating size and horsepower war in 1981, they had one more trick up their sleeve for 1982.