SuperJet 61x 701 problem

[Barbieri972]

Hey I have a 1994 SN superjet.
It has a 61x motor with a single SBN 44mm

I rode it all last season and half this season with a factory pipe pipe and water box with a 115/140 95 gram spring for jetting.
I recently just rebuilt the top end with pro x pistons and put an ADA head with 35cc domes. I re jetted it to 120/145 95 gram spring. I've taken the ski out twice now and both times it runs like poop. It ran great in the garage on the stand after I broke it in and re jetted it, I never had heard it run that crisp and smooth before. As soon as I got it to the lake it ran okay (not great) for a minute then it would not rev out, it would just sputter from 1/4 throttle on. (I've tried with hood off as well its not an exaust leak)

These are the problems I'm guessing I have but I wanted some people input,

-bad cool
-bad stator
-bad head gasket
-jetting too fat?
-plug wires need to be snipped

Idk if anyone has some input I'd appriciate it, I was stoked to get it all done I just want it to run as good as it should. And I know it's a 2 stroke so it can't be anything major but I'm frusterayed and can't figure it out

 

[scotts2t]

You could have water getting into cylinder from a pinched or ripped head o-ring.

 

[INDebtSJ]

You can turn the air mixture screws to a 1/8-1/4 turn out and start from there. If it runs better then you know what direction to go on jetting.

You will have steam come out of the bypass or a clean piston if its a head gasket.

 

[Fleabags]

Your jetting is the same as mine with a similar set-up. However, what made you richen it up? Increasing compression doesn't require you to re-jet. Have you verified compression since the rebuild to be sure your rings are seated and all is well?

 

[Barbieri972]

You can turn the air mixture screws to a 1/8-1/4 turn out and start from there. If it runs better then you know what direction to go on jetting.

You will have steam come out of the bypass or a clean piston if its a head gasket.

I have a solid stream coming out my bypass but if it's leaking I think it's very little, ive played with the screws and it does a little but not much, still doesn't ever rev out

 

[Barbieri972]

Your jetting is the same as mine with a similar set-up. However, what made you richen it up? Increasing compression doesn't require you to re-jet. Have you verified compression since the rebuild to be sure your rings are seated and all is well?

It never really had the bottom end I wanted so that's why I changed jetting, everywhere I look says that's what I should run, so I don't think that's the problem

 

[Barbieri972]

Well I think I might of figured it out! Pulled the head and the front piston is squeaky clean so thinking I have a head gasget leak, putting it back together and crossing my fingers that it'll run good!

 

[INDebtSJ]

Yep

 

[Barbieri972]

Well still no luck, ski ran bitchen at home, and took it to the lake and it did the same thing, has anyone had a stator or Cdi go out? I'm at a loss right now and don't know what else it can be

 

[INDebtSJ]

Thats the way it always goes. There is no load on the engine.
Seems to have a lot of scoring on the cylinder walls for new pistons. Whats the compression?
Did you disconnect the overheat sensor from the ebox after the new head?

 

[Barbieri972]

The compression is 185 psi, and yes I disconnected it

 

[bach6177]

From the looks of the clean piston Somthing is up with the front cylinder.


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[tomski]

You can turn the air mixture screws to a 1/8-1/4 turn out and start from there. If it runs better then you know what direction to go on jetting.

Those are fuel mixture screws.

 

[Barbieri972]

I've tried going everyday on the screws it doesn't help, I'm
Thinking its a bad CDI, cool or stator

 

[Barbieri972]

Finally got her ripping! Ended up being bad spark plug caps. They had tears and were arcing out