97 Superjet

[standupwannabe]

Just registered today. This is my first post (hopefully I don't screw up). Cheers to everyone. Rode 650sx's years ago but upgraded to a boat when kids came along. Got the itch big time to get back onto a stand-up, so when I came across a 97 superjet with numerous mods at a dirt bike dealership I picked it up. The problem is that the dealership picked the unit up somewhere in Washington or Oregon and they have no history on the machine. Obvious mods include "B" pipe, msd ignition/leads, worx intake grate, jet dynamics plate, tau ceti arrestors/riva adapters, greater yamaha girdled head, s/s impellor, umi bars & steering kit, pole shortened 2", side sponsons, bilge pump. I trust the guy that sold it to me when he said that it goes like hell compared to the stock 04 sxr he also has for sale. My questions are as follows:
1- There are two lead fishing weights (@ 5-10lbs) epoxyed inside the hull behind the engine. Are these to prevent porpoising during racing. Sould I remove them for freestyle/play riding?
2- The impellor appears flawless, however, it looks like it has been "ground or polished" on the faces of the blades. I can't see any markings on the unit looking down the shaft so I don't know the brand or pitch. I've read something about impellors being "shaved" What is this, and does this sound like my impellor?
3- Is there any way of telling if there is aftermarket reeds on the boat without removing the carbs and ruining the gaskets?
4- Unit has twin Mikuni carbs. How can I tell if they are stock, or modified? Should I look for obvious markings or modifications?
5- Lastly, I am a little worried when I checked the compression. I am only getting 145# on both jugs with my cheap compression guage. I thought that I should have more with the girdled head. I am going to pick up a snap-on gauge and recheck next week. The question is, how can I tell the displacement (cc) of the domes in the head. I checked Greater Yamaha's website and they don't even list this head anymore. I'm not sure if I can even get replacement domes for this head. If the boat was set up for racing, what would be the best guess on dome displacement? If it sounds like the top end is getting tired, are there consequences to riding this way for another season, or will it just lack power. Does lower compression reduce bottom end power, topend, or over the entire powerband?
Thanks in advance.

 

[WaveDemon]

1- There are two lead fishing weights (@ 5-10lbs) epoxyed inside the hull behind the engine. Are these to prevent porpoising during racing. Sould I remove them for freestyle/play riding?

Take them out! they are there for racing only.

2- The impellor appears flawless, however, it looks like it has been "ground or polished" on the faces of the blades. I can't see any markings on the unit looking down the shaft so I don't know the brand or pitch. I've read something about impellors being "shaved" What is this, and does this sound like my impellor?


Skat-trak impellors have that type of finish. you won't be able to tell what it is untill you take it out. the modle # is between the fins.

3- Is there any way of telling if there is aftermarket reeds on the boat without removing the carbs and ruining the gaskets?

No. don't worry about it unless you have no low end with could mean busted reeds.

4- Unit has twin Mikuni carbs. How can I tell if they are stock, or modified? Should I look for obvious markings or modifications?

you probably have flame arestor adapters on the top. how many bolts hold them on? 3 or 4? Look tosee if they are taper bored. if so they'll be wider on the top. also look to see if the venturi (bomb site) is still there when you look down the carb.

5- Lastly, I am a little worried when I checked the compression. I am only getting 145# on both jugs with my cheap compression guage. I thought that I should have more with the girdled head.

stock is 150 psi. check with another gauge. there might be a bad reading. also someone might have put a head gasket in there when they shouldn't have. it uses o-rings only.

I am going to pick up a snap-on gauge and recheck next week. The question is, how can I tell the displacement (cc) of the domes in the head.

it will be marked on the dome when you take the head shell apart. make sure you have an extra o-ring kit before you crack it open the o-rings might need to be replaced.

I checked Greater Yamaha's website and they don't even list this head anymore. I'm not sure if I can even get replacement domes for this head.

you can still by domes from greater but they are not making anymore. if you can't buy from them they are the same domes that riva uses. the dome might need to be slightly modified on a cooling fin to fit in the lock. open it up you'll understand quickly.


If the boat was set up for racing, what would be the best guess on dome displacement? If it sounds like the top end is getting tired, are there consequences to riding this way for another season, or will it just lack power.

if you are getting blow buy your just get more blow buy. whenever you re-build check out the crank.

Does lower compression reduce bottom end power, topend, or over the entire powerband?

it lowers power everywhere it's most noticable down low.

Thanks in advance.

you're welcome

 

[ItsRixter]

Just registered today. This is my first post (hopefully I don't screw up). Cheers to everyone. Rode 650sx's years ago but upgraded to a boat when kids came along. Got the itch big time to get back onto a stand-up, so when I came across a 97 superjet with numerous mods at a dirt bike dealership I picked it up. The problem is that the dealership picked the unit up somewhere in Washington or Oregon and they have no history on the machine. Obvious mods include "B" pipe, msd ignition/leads, worx intake grate, jet dynamics plate, tau ceti arrestors/riva adapters, greater yamaha girdled head, s/s impellor, umi bars & steering kit, pole shortened 2", side sponsons, bilge pump. I trust the guy that sold it to me when he said that it goes like hell compared to the stock 04 sxr he also has for sale. My questions are as follows:
1- There are two lead fishing weights (@ 5-10lbs) epoxyed inside the hull behind the engine. Are these to prevent porpoising during racing. Sould I remove them for freestyle/play riding?
2- The impellor appears flawless, however, it looks like it has been "ground or polished" on the faces of the blades. I can't see any markings on the unit looking down the shaft so I don't know the brand or pitch. I've read something about impellors being "shaved" What is this, and does this sound like my impellor?
3- Is there any way of telling if there is aftermarket reeds on the boat without removing the carbs and ruining the gaskets?
4- Unit has twin Mikuni carbs. How can I tell if they are stock, or modified? Should I look for obvious markings or modifications?
5- Lastly, I am a little worried when I checked the compression. I am only getting 145# on both jugs with my cheap compression guage. I thought that I should have more with the girdled head. I am going to pick up a snap-on gauge and recheck next week. The question is, how can I tell the displacement (cc) of the domes in the head. I checked Greater Yamaha's website and they don't even list this head anymore. I'm not sure if I can even get replacement domes for this head. If the boat was set up for racing, what would be the best guess on dome displacement? If it sounds like the top end is getting tired, are there consequences to riding this way for another season, or will it just lack power. Does lower compression reduce bottom end power, topend, or over the entire powerband?
Thanks in advance.

#1 Yup that was a racer trick. Low center of gravity improved handling. Rip them off for freestyle since it's all about weight. I have a pair of "rayce" weights that bolt to engine mounts.

#2 If it's only on the ends then it sounds like a cheap fix/repair to a chipped blade(s). If it is a uniform sanding all over the prop it's likely redone by a company like impros (new skat traks have that finish also). You need an small angle mirror and a bright light to check the brand and pitch of the prop if you are not planing on removing some bolts. The info is on the back (rear) end of the prop.

#3 ??

#4 Pull the airfilters and measure the opening. Check for the choke (hopefully removed). see if it looked honed. that's all I know but other here are better carb experts.

#5 145 psi compression on a 1997 ski isn't too bad. The fact that there are even is key. I can't remember what stock compression is but I thought it was 135??? It's not the head but the domes that create compression...no way to know unless you pull it off.

Just leave it alone and ride for a while...then start messing with it is my recommendation...except the weights...take 'em off!!!

 

[Speedfreak]

Just keep on reading this site and all of your questions will be answered as you learn about your new ski. If you are used to the old 650s then I would leave the ski alone for this year and then figure out exactally what you want out of a ski.. Wether you want an all out freestyle low end monster or just a freeride ski that has a good bottom end hit but enough speed to race others at the lake.

Either way you will want footholds. That sounds like the only thing the ski didn't have.

I would take the eletrical box apart to see if there is an MSD enhanser in there you don't need a gasket for that one. And pull the head to see what size the domes are. If you want more compression then you can get a set of domes but I would leave it alone and just RIDE. The low end hit will be amazing compared to the ond 650's

 

[standupwannabe]

Thanks to everyone for the advice. First things first, the lead weights are coming out! Here is what I found out:
1- Borrowed the neighbors snap-on compression guage. Got 180# on the front jug and 185# on the rear jug! Yippeee. I'll be able to sleep tonight.
2- Checked the carbs (no choke, only a primer) and the internal bores appear somewhat untouched. There is some slight rub or machining marks on the first 1/2" of the internal bore, but I don't think that this is what you guys refer to as a taper bore.
3- Checked impellor with a mirror & flashlight. It is a Solas 13/17 (and the polishing marks are not on the ends of the blades, but all over the faces of the blades) I would use the example of a cylinder hone, but on the faces of the impellor (front & back). Is this a good set-up for freestyle/fun riding?
4- I will leave this question for another time (along with a pic for clarification), but the inside of the hood cowl has a cut-out, and an extra water line that goes nowhere (except to a hull umi discharge fitting ). I don't know much about race set-ups but I have to assume that a "big fat" pipe was in the boat at some point. Could this be the reason for the redundant water line?

 

[WAB]

Congrats on choosing the modded SJ! :biggthumpup:

oh yeah, post up some pics.

 

[Hogggman]

Congrats and condolences you are about to have an addiction for which there is no cure

 

[Speedfreak]

Since it is a solas are the leading edges of the blades curved in a radial shape or are they straight. The radial leading edge is a concord prop which is the prefered prop for freestyle skis.

If the filter adapters have 3 bolt holes the carbs are 38mm and if they have 4 bolt holes the carbs are 44mm.... What color are they?

Does your intake look like this ebay auction here is the number. Item number 270046801016 you will have to past this in the search bar I can't get the bloody linky thing to work But anywho If they look like that then that is Great!! you couldn't ask for anything better

 

[keefer]

"Ebay Ad" link no worky. :clown:

 

[Speedfreak]

I can't get the linky monster to work with me on this one so I updated it with just an item number Thanks for catching that

 

[standupwannabe]

I had a look and the leading edges of the impellor (looking down the grate) are very much curved. Looking in the rear of the jet, the trailing edges are straight across.
I'm not sure if I'm looking at the correct bolts, but when I pull the arrestors off, there are three allen head bolts holding down the adapters. The adapters are red anodized "Riva Racing" models. The reason that I was wondering about the carbs is because there are a bunch of fancy colored hoses and tee fittings coming out of each carb (including a couple that have blanking plugs in them). Not sure what they do but they look nice
I appreciate all the pointers. I think that I'm hooked on this site already.

 

[keefer]

Welcome to the X. :biggthumpup: You gonna like it here, lots of good people, info, and good times. Get your wetsuit on and ride that thing so you can get the addiction started. One of the most fun things you can do with your clothes on.:clown:

 

[Shonuff]

Great ski, it won't go like hell compared to an SX-R but it's a great setup.

 

[standupwannabe]

Hey Shonuff. It's funny that you say that because I had the choice of the SJ and a bone stock 04' sxr in the dealership. The reason that I went for the SJ had nothing to do with performance. but only because of the weight. I have no trailer, and I need my wife to help me load the machine into the back of my pick-up truck, & since the SJ was 50lbs lighter, I went with it. How sad is that? I know that freestylers prefer SJ's & racers demand sxr's, and I'm not here to start a war on one machine over another, but I'm interested in knowing how my boat will compare to that other machine (sxr) that I passed up. In other words, will they not both do about 50 mph? (SJ modified & sxr stock). How about stability in the chop? (SJ with sponsons and sxr stock). I have a feeling that the sxr will turn much better, but which machine is more stable once it is airborne off a wave? I guess what I'm expecting to hear is that you can't go wrong with either choice. Sorry if this question has been beaten to death, but I just thought that I would ask.

 

[swanny]

where are you and where are you going to be riding this?

 

[GDFL]

Glad to see you made it over here. This place is definitely home for most standup riders. Let's see some pics.
Garrett
mb112 on the other site

 

[Mark44]

Ride that thing like you stole it and keep reading this site. We will spend your money for you.

Mark44 Brap!

 

[Shonuff]

Hey Shonuff. It's funny that you say that because I had the choice of the SJ and a bone stock 04' sxr in the dealership. The reason that I went for the SJ had nothing to do with performance. but only because of the weight. I have no trailer, and I need my wife to help me load the machine into the back of my pick-up truck, & since the SJ was 50lbs lighter, I went with it. How sad is that? I know that freestylers prefer SJ's & racers demand sxr's, and I'm not here to start a war on one machine over another, but I'm interested in knowing how my boat will compare to that other machine (sxr) that I passed up. In other words, will they not both do about 50 mph? (SJ modified & sxr stock). How about stability in the chop? (SJ with sponsons and sxr stock). I have a feeling that the sxr will turn much better, but which machine is more stable once it is airborne off a wave? I guess what I'm expecting to hear is that you can't go wrong with either choice. Sorry if this question has been beaten to death, but I just thought that I would ask.

The SuperJets are defiinitely lighter and will be easier to load. Unless your wife is amazingly strong, however, having her lift her share of a seven foot long 291 pound load is going to be tough.

They should run about the same speed. When you stated that it "goes like hell compared to an SX-R" I though you creating a relative value with the Kawasaki that the Yamaha surpassed.

The SX-R will outrun it, out-turn it, out stabilitize it but the SuperJets are simply more fun in the waves. You really could not have gone wrong either way.

Time to add an SX-R, an Octane, and a Hydrospace.

Good luck and great buy.