Super Rok exhaust power valve problem

Hi guys,

I think I have a problem with my Super Rok engine valve as the engine doesn’t have so much power as last year. My friend noticed that valve doesn’t go up and down as should be (his idea). He doesn’t know the Vortex Super rok /Rok GP engines, he is more like a Rotax guy, but he told me, that valve works almost the same on every engine among engine manufacturers.
Do you have any manual or tips on what needs to be changed or checked? It looks like that shaft has a tolerance (moving a little bit), so there could be some leak.
First I want to check the carburetor if it’s clean and if every jet is torqued and then look on the reeds, if is not a problem there and then I want to look at that valve.
The engine has not good mid-range as it should be
Every idea will be appreciated.
Is there anyone who own this SuperRok engine? New ROK GP power valve is fully automatic I guess. I am not sure if the inside of that SuperRok exhaust valve is the same as the RokGP exhaust super valve.
New ROK GP valve

SuperROK valve

Thanks in advance

Yes I have just sold my Super Rok. Make sure that the valve sits perfect in the cylinder, and can move very easy up and down, if you remove the top cover, and move it by hand. Allso make sure its clean from carbon deposit, same goes for the hole the valve sits in. Finally check for any leaks around the membran.
Have you played with the tension on the valve with the red plastic screw ?? My motor builder told me to screw it all in, and back out 10 notch. SuperRok is more a “top rev. performer”… my x30 has a better mid range than my old SuperRok.

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So i removed that valve. It looks little bit messy, I tried to move it with hand and I need some force to pull out . There is a huge play on that shaft and I noticed that gilotine has a thread so it could be move up and down. I never tried to move with that plastic screw.
Maybe that shaft/gilotine play its not a problem as that membran seals, but I am not sure.
I made two videos, but i need to upload somewhere as there cant be uploaded.

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Maybe watch this video. Its for a rotax… but the princip is the same : How To Service The Rotax Senior Max Power Valve - POWER REPUBLIC - YouTube

Btw. are you using two springs ?? One on each side ?? The old diagrams for the super rok, are only showing one spring… But my motor tuner told me they run much better with two springs, like on the Rok GP…

Vortex SuperRok

Vortex RokGP

Thanks, I will check that video. I saw only one spring. I need to disassemble the whole valve, so there could be another one inside

I wanted to jump in here because I saw Vortex. New to karting and had a question about the exhaust for the Rok Shifter engine. Is there a gasket between the pipe and engine and if so where can I find it?
Thank you for any help.

I´ve noticed that SuperRok power valve is the same as Vortex Max power valve, which both have only 1 spring, but ROK GP power valve looks very similar but has 2 springs and my power valve also has 2 springs, so now I am confused if it’s for some “better response” purpose or its mistake made by the previous owner…
Could someone explain? Thanks

And you did not read my reply above ? Regarding the two springs ?

Sorry Brian, I read it, but I forget it. So , ok, I will put that second spring there again . Thanks :smiley: