SN Superjet fix and improve build

[lcgordon]

Hey guys,
I bought a 1992 SN a couple of months ago. I have ridden it about 5-6 times and it has been a lot of fun. It is mostly stock so I want to do some things to it to make it better and also fix lots of issues. I had a post over In the superjet area but wanted to do more work to it and keep it going more as a build. I figured I would document it here.

Here is the ski as I bought it.

A couple rides in I cracked the tray bad so I fixed it and put some NOS turf on it to get me through the summer.




I then decided the 650 is just too slow so I needed to find a 701 to drop in. I ended up finding one that was drop in ready bone stock from a superjet. Finally got it to my house and it would not turn well by hand. Ended up pulling the head and saw this rust bucket. I emended up getting all my money back. I now have one on the way that has a head, msd, vforce reeds and other than that stock. It should be to my house soon.


My goal now is to get this motor in and ride it until it gets cold. I also got the pipe below a Riva Freeride drypipe and will be putting it on the ski when the new motor goes on. The ski needs a new pump shoe because the plastic one is broke, it needs one of the inserts on the intake grate and ride plate fixed. And because of the huge crack I would like to cut the tray out and defoam and do foot holds. I will continue to post all of that stuff in the future.

 

[lcgordon]

See MtrHead's write-ups on his Square Nose 701 Conversion Build to a Hot 60 mph Vintage Buoy Rocket for guidance.

Yet another square nose build - PWCToday

Here you can have a thread all to yourself, about whatever PWC build you are working on.

www.pwctoday.com

Thanks for that. I will.

 

[lcgordon]

The motor removal has been started.

 

[kevbo]

All used PWC engines should be considered rust buckets. The chances of finding one thats good is very slim.

 

[lcgordon]

I think i found a decent one. Time will tell.

 

[Stavissimo]

Just get it rebuilt who cares

 

[Stavissimo]

@Jr.

 

[Sanoman]

Sub’d

 

[Jr.]

@Jr.

Thank you, good used, and built motors in stock

 

[lcgordon]

Just get it rebuilt who cares

The goal is to keep this semi budget, it has perfect compression so I’m going to run it for a bit. Need to save money for the hull fixes.

 

[lcgordon]

I got the motor. All seems to check out so far. So ready to get it in the ski. I forgot to buy extra fuel line and some tees for 1/4” so I’ll need to go buy some locally.

 

[lcgordon]

We’ll that was the worst. Now I know why ppl run b pipes haha. I need to figure out a better way to get the motor an pipe in. I wonder if I mounted the full pipe on the motor first. I had to pull the motor in and out about 4 times. I thought I was not going to get it. I finally did I think. It seems correct. I just need to get the fuel lines done and the water lines done now.

 

[lcgordon]

Finalized the ski today and got to take it out this morning. It is a bit cold out but not too bad. First think it was not pissing so I was scared to ride it. Figured out I had the two exhaust stingers flipped. I leaned it out a tad and up top it was great. Down low is a bit rich still. I need to mess with it more and check pop off pressure. It was fast tho and so much more fun.

 

[lcgordon]

One issue is the throttle is really hard to pull. My finger was getting pretty tired. I know with the single carb the throttle plate is on the other side of the carb. So the cable is really long. Now it kinda does a loop so it can be on the front of the carb. Not sure if that is causing it? I know it is two carbs to open now but I don’t think that would make it that much harder.

 

[DylanS]

One issue is the throttle is really hard to pull. My finger was getting pretty tired. I know with the single carb the throttle plate is on the other side of the carb. So the cable is really long. Now it kinda does a loop so it can be on the front of the carb. Not sure if that is causing it? I know it is two carbs to open now but I don’t think that would make it that much harder.

Hard bends in the cable and worn cables can cause a hard pull. You could have someone work the throttle for you while you move the jacket around to see if it gets any better.

 

[lcgordon]

Hard bends in the cable and worn cables can cause a hard pull. You could have someone work the throttle for you while you move the jacket around to see if it gets any better.

Smart I will try that. The throttle was all good with the 650 in it last week so I would think the cable is fine and that it’s routing.

 

[lcgordon]

Has anybody ever used these. They are so cheap. I think I would like to try them for 60 bucks.

Standard Footholds SXR Superjet 550 440 Octane AM Hulls 750 SX | eBay

Standard footholds for all stand-up's.

www.ebay.com

 

[lcgordon]

Does anybody know why the my ski and my 650 was also, are hard to start without a bit of prime? Seems like kind of a tuning issue?

 

[DylanS]

If you’re having issues on initial startup for the day the reason typically is that fuel pressure leaks down from bad sealing at fuel line splices (mostly on external fuel pump setups) and carb parts mainly needle/seat o-ring.
Almost all skis that sit for extended periods of time will have a little trouble starting without being choked or primed to some degree.


If you’re having issues with starting every single time then you could have a variety of issues. Low compression, worn reeds, leaking seals, a fuel condition, poor spark, slow cranking.
I’d start with a pop off gauge and inspection of the seat o ring and needle.

 

[lcgordon]

If you’re having issues on initial startup for the day the reason typically is that fuel pressure leaks down from bad sealing at fuel line splices (mostly on external fuel pump setups) and carb parts mainly needle/seat o-ring.
Almost all skis that sit for extended periods of time will have a little trouble starting without being choked or primed to some degree.


If you’re having issues with starting every single time then you could have a variety of issues. Low compression, worn reeds, leaking seals, a fuel condition, poor spark, slow cranking.
I’d start with a pop off gauge and inspection of the seat o ring and needle.

Thanks for that explanation. Something to get into here soon when its too cold to ride. I want to get some riding days in the next couple of weeks. It does fire right off when i give it a bit of fuel down the carb. I need to set up the primer. Just have not had time yet.