Deal With It, Another 650SX Build

tigmaster · 12-16-2009, 12:39 AM

Hey all, new to the site and to the world of water. Been riding dirtbikes for years along with any other motorized item minus a ski. Super mechanically-inclined and will be doing all the work myself but I need your suggestions on how to set this ski up for some light freestyle. Obviously when I say freestyle I mean just making the ski much more agile and responsive. I know I won't be seeing any extreme tricks with a 95lbs hull.

So now on to the important stuff...

From what I have been reading, people generally trim down their 650 hulls by about three inches. Is this true? If so, does anyone have a link or any input into where I should cut it at and how much shorter I should make it? Next is grab holes cut into the front sides of the hull. Where should I position them at? I also plan on glassing over the extinguisher cap and ditching the fuel door for an open cap setup. Are there any other things that need to be addressed while in the fiberglass stage? I have heard about reinforcing the hull but haven't found any real info on it. Any suggestions there?

Once done, the inner hull will be gel coated white. Hull paint scheme will be red-based plaid on the upper hull with the lower most likely black.

Now onto more things. I have tried to figure out what impeller to get for freestyle-based riding but I am unsure. I also need a ride plate but don't know about that either. Concerned about the length of the plate along with the hull triming. Besides that I will need to select a pipe and engine internals.

I will also be fabing up a custom handpole so any suggestions or things to consider there will be appreciated. I have a basic design but haven't finalized anything.

So let me know what suggestions you have or feel free to flame about me asking repetitive questions.

PrickofMisery · 12-16-2009, 12:50 AM

Freestyle? 1st thing you need to do is trade it for a Yamaha.
All kidding aside (except for the Yamaha part) you picked one of the heaviest, least favorable skis as a foundation.
You said to flame so I did.

No with that being said, you havent mentioned motor/year. Typically the shorter the pole the eaasier to trick. The Coffman, PJS and Factory Pipes are best. You may also want to consider a head to go along with your exhaust. The pre 91 motors had really small carb that need to be ditched. As far as impeller pitch, I recently installed a 15 in an X2 with a pipe, head and 44SBN and it hits good from about 3000-4000 RPM

PrickofMisery · 12-16-2009, 01:01 AM

By the way, welcome to the Board!

tigmaster · 12-16-2009, 01:01 AM

Oh jeez, now I'm looking like a newb here leaving out important details.

It is a 1988 with a stock motor and a 44mm carb. Intake manifold is not stock and is also 44mm bore. No clue on brand.

Any suggestions on hacking away at the hull?

PrickofMisery · 12-16-2009, 01:39 AM

Not on the shortening part. One thing I will tell you is cut as much weight as is possible cause that hull is heavy. In all honesty I gave you the best suggestion in my first reply. There are other option though for your power and drivetrain......

ghostrider117 · 12-16-2009, 09:19 AM

welcome to the board.

take this from a guy who has been beaten up on here about the 650sx.
sell it,buy a superjet!
i built 2 nice 650's and they are turds.they float but who wants to ride a floating turd?
i put a 750 big pin in one and it was a screamer but when it came to freestyle,they are tooo heavy!.
RACING=HEAVY+HP=CHOP CUTTER
FREESTYLE=LIGHT+ HP=BACKFLIPS
GET THE PICTURE?

upstand2 · 12-16-2009, 09:20 AM

650's are a lot lighter then 750's but they porpoise very easy, I don't think you want to shorten it. In fact I extended my ride plate 5" and it still jumped fine and I'm a hefty 220lb. I'd say get the drivetrain sorted out, ride it and tune the hull from there.

ghostrider117 · 12-16-2009, 09:21 AM

HEY PRICK, THAT FELT GOOOD!

tigmaster · 12-16-2009, 09:34 AM

Does anyone actually have the specs as far as weight goes in comparison of a Superjet and a 650SX? Like I said, I weighed my hull and with all the bumpers still on, the inner mount plate for the handpole, and some random straps it was exactly 100lbs. I know the bumpers are more than five pounds themselves and the plate is at least one so let's just say 94lbs for the hull. Isn't that reasonable? I see CF hulls weighing in at 70lbs and granted that is almost 25lbs lighter right there but I am a small guy. Yea I also know the Superjet has an extra 25hp stock to start with too.

See my problem is that I am another one of those guys who got a ski real cheap, $600 to be exact so it is hard for me to not just deal with what I have. So you guys think that even though the ski offers so many places to shave weight like the engine mount plate, handpole, and hull itself that it still won't be enough to do anything useful with the ski?

ghostrider117 · 12-16-2009, 09:53 AM

they are just plain bulky to ride. find an x-2 to put the motor in.
i built a 550/650 conversion wich is a 650 motor in a 550 hull=freestyle fun.
you need to remember that lighter is better for what you want.
build a conversion ski.dude you can build everything yourself (motor mount bed plate,if your the aluminum man.(tig master).you can pick up a 550sx hull for a couple of hundred bucks on clist and then start the build.
hell i'll sell you mine!.