The variety of gears has a little to do with the same chaincase being used by a variety of Kawi models with different horsepower and different potential for top speed.......Intruder, 340 Invader, 440 Invader, LTD's, Interceptor.
The factory shop manuals show the stock gearing.
I can't remember the actual gears, but I remember the 340 Invader had a "theoretical" top speed of 79 MPH with the clutches at .96 overdrive (fully shifted out) and the engine running at 8000 RPM. The 440 was geared to hit 88 MPH with the same conditions.
A very well set up 440 in ideal conditions has certainly achieved 90 MPH.
My 1st Invader that I bought in 1982 had a couple tweaks done by the original owner.
One of the changes was a gear change that showed a bit quicker gearing....the chart in the manual showed it would have a "theoretical" top speed of 84 MPH.
I completely agreed with this change.....I might give up a little on top end, but normal riding on trails, etc. I would have a little quicker acceleration. I just don't have any area near me where I could safely try to get to 90 MPH. Certainly if you were participating in a radar run on a frozen lake, you would want the taller gearing. A lot of sleds use a chain tensioner that you can adjust with a bolt and locknut mounted on the chaincase.
The Kawi's use those plastic pucks and tensioner spring. Changing the gears often requires changing that tensioner spring, and sometimes the chain length to accommodate the change in size of the gears....the factory shop manual shows exactly the proper chain and tensioner spring to use with the various gearing.
The 1982 Interceptor is a perfect example....it won the 1982 SnowGoer shootout. It smoked every other sled in the 1/8 mile....the SkiDoo Blizzard 9500 actually crept by it once the sleds reached top speed. Similar weight sleds...similar horsepower.
Strictly a function of gearing...an Interceptor owner could have changed the gearing to gain 3-4 MPH on top end if their "thing" was lake racing....or the Blizzard owner could have dropped the gearing in his sled to gain a little quicker acceleration.
You have to choose...you can't maximize both acceleration and top speed.