I recently posted this basic info in another thread. So, I updated it with a little more info. Hope it helps.
Here's what I know or what I have read and learned from the knowledgeable people here:
Pre-1994 Square Nose Super ("SN") Jet ("SJ") are 650cc engines, which are fine to get into the sport especially if they are unmolested and you are relatively light, say under 175 lbs.
The 1994-1995 Square Nose SJ have the same bottom hull as the 1996-2007 Round Nose ("RN") SJ. This bottom hull is more freeride/freestyle oriented than the bottom hull on the 2008-2020 RN SJ which is more buoy course race (i.e., carving) oriented.
The 1994-1995 SN SJ has a 61x 701cc engine with a single SBN44 carb. The 61x has a little more power at low rpms which makes it more freeride/freestyle oriented than the 62t which makes more power at higher rpms which makes it more freeride/race oriented.
The 1996-2020 Round Nose SJ have a 62t engine with dual carbs, which makes more horsepower than the 61x engine and are more difficult to tune because of two carbs.
A 62t engine with a 61x cylinder is the best of both worlds because you have the bottom end of the 61x with the extra hp from the dual carbs of the 62t.
The bottom hull on the 2008-2020 RN SJ is more freeride/race oriented (i.e., carving) than the 2007 and older SN SJ and RN SJ.
The top hull and handle pole on the 2008-2020 is more preferred than the pre-1008 SN and RN SJ.
From what I can tell from reading here, the cat's meow is a 1996-2007 Round Nose SJ because it has the playful bottom hull of a Square Nose, but the better top hull/pole of the Round Nose.
All engines in anything you look at may have been replaced. In fact I bought a 1994 SN SJ which I thought had a 61x 701cc single carb engine in it.
But lo and behold it had a 6m6 650cc which I did not know because of my ignorance. So watch out.
All of the engines above are 2-stroke engines which require the mixing of 2-stroke oil and gasoline.
The 2021 and newer SJ is a 4-stroke engine which runs regular (i.e., unmixed) gasoline. It is a larger and heavier SJ than a SN or a RN SJ. The 2021 and newer SJ is not oriented towards freestyle at all. However, it is a phenomenal freeride/racing carving racing machine. Some love it, some have sold theirs to go back to the lighter, less powerful more freestyle oriented SJ's.
It is up to you to know what you want from your SJ. However, you won't know what you want until you start skiing. So your focus should be to start skiing as soon as possible. Your first ski will be your first ski. You may sell it or let your wife or kids use it, but It will not be your last ski.
The FX-1 is truly a unicorn. Only 1500 were made worldwide and they were only made in 1994 and 1995. They are like a Kawasaki 550sx on steroids. They are not as forgiving as a 550sx. Very few people can ride them well. The best rider I personally know has a 1995 FX-1 which he can ride phenomenally. But he generally prefers to ride his pre-2008 RN SJ. He also surfs his RN in the ocean. Still he can do anything with the FX-1 that he can do with the RN, he just prefers the RN. But he is an exceptional rider with over 40 years experience.
Advice: Get a SJ with a 701cc of any variation in great shape and ride it.
I have been told to learn to tune it properly along with adding a B-pipe and later you will have even more than enough power.
However, to get you into the sport there is nothing wrong with a 650cc SN SJ to start as long as it is relatively inexpensive.
One more thing. If you would prefer to learn to ride over preferring to learn to wrench on your ski. Buy the least molested ski out there. There have been so many skis which were "modded" by unknowledgeable people out there that it will take hundreds if not a thousand dollars to bring them back to reliability.
Like
@Quinc says: "Buy a Super Jet."
