Here are basic instructions, websites and pictures for installing the RIVA Gas Operated Powervalves.
Here is a website showing the removal of a Sea-Doo RAVE Valve assembly. Same set up basically.
There are a few other minor things to do when installing the Riva gas valves.
Here is a good diagram showing how the Sea-Doo RAVE valve setup is installed.
Basically the same. (good for a visual insight)
Also check here for some more RIVA Gas Valve install pics/tips
Gas Valve thread(s)
Expanded diagram of RIVA Gas Powervalve

Remove all OEM hardware
Remove the Exhaust manifold; easier to install
Some minor modifying may need to be done to help proceed with the installation of the gas valve adapters.(at your own risk); I don't recommend grinding, but it is possible fitment may be easier for installer.
Plug ends on cylinders where the factory powervalve shaft went thru with JB weld or high temp silicone; let dry fully
. Or drill and tap and plug with allen set screws.
clean mounting surfaces well.
Install valve (in correct position); only goes in 1 way notch facing down
Intall Gasket
Install Gas Valve billet aluminum adapter(s) over valves
Apply blue loctite on bolts and Snug down bolts well; (hand tight); do not overtighten !
Leave #1 cylinder bolt top closest to cylinder head out so you can install the ground wire from the front case cover to the billet gas valve adapter.
Install ground wire via billet adapter bolt; tighten well.
Install rubber lower bellows on base of billet adapter. Apply Zip tie.
Wet down rubber bellows with glass cleaner well.
Screw on and install the top cap on the gas powervalve stem threads. Do not overtighten !
The purpose of the glass cleaner is to help allow the installation of the lower rubber bellows to slide/pop on the top screwed on cap that screws on the valve stem threads.
Apply the provided spring around the circumference of the cap & rubber bellows. Look under the bellows and make sure that the rubber bellows is not twisted in anyway. This can cause a tear in the rubber over time and wrinkle the bellows. Pay Close Attention to details !
If the spring is to not be used, a zip-tie is needed for installation to secure the lower rubber bellows to the top bellows stem cap. In this instance if a zip-tie is used, a small notch will need to be cut on the bottom of the black top cap to allow the zip-tie end to travel the full length top>bottom w/o hitting the cap.
Slide all three gas valve(s) up/down and check to see if there are not any binds or dragging felt.
Install Exhaust manifold after modifications have been done to proceed with the installation of the gas valves
On my motor, the #1 gas valve black cap needed to be cut down 3-5 mm. the is to allow the black cap to fit under the exhaust manifold w/o hitting the pipe. Or as the link above shows, grinding can be done to have the cap fit fully. I chose to not grind on my exhaust pipe as it is jacketed !
Adjustment of the retainer spring on top will need to be done to allow for the shorter height in the top cap.
Test fit peices.
Install return spring provided in kit on top of bellows cap; concurrently, install black top cap and flip retainer spring over for fitment.
The installation is now finished. You will need to do some tuning to adjust the red adjuster cap on top of the black cap to fine tune it to the characterisitics of your motor. Not everyones motor is the same !
Guys, for those of you who have gas valves, please add to this thread if you feel there is something I left out or can be taken out (edit) !!!
I hope I covered most/all of this
Also, if you look at my number # 1 cap, you can see it is shorter.

Take Note of the Notch I cut for the Zip-Tie around the bellows to travel.
Others use the spring provided.

Note the Ground wire Attachment and the height of the black cap on this number # 1 cap. It just clears the pipe!! The Cap has been cut about 3-5 millimeters in order for it to clear the pipe.
You can use a hacksaw or dremel tool to cut the cap. Cut it even all the way around !

Note where I did not grind on my pipe. I used a blade screwdriver and popped the spring to wedge under the hump on the pipe. Holds every secure; over 3 years now.

Important Note: I can't give advice to where the red adjuster needs to be set at, everyone's motor is different. Instructions should also be provided with a new kit. RIVA Yamaha can also help provide assistance to obtain the factory original instructions.
I also do not recommend grinding on the OEM pipe as it is jacketed. Any grinding that is done, is done at your own risk.
Proper fitment of valve must be verified by user prior to assembly. The valve only goes in 1 way, please ensure the valve is properly installed prior to assembly or possible engine damage can occur.
These steps listed above is only a guideline and you are installing the item at your own risk.
Here is a website showing the removal of a Sea-Doo RAVE Valve assembly. Same set up basically.
There are a few other minor things to do when installing the Riva gas valves.

Basically the same. (good for a visual insight)
Also check here for some more RIVA Gas Valve install pics/tips
Gas Valve thread(s)
Expanded diagram of RIVA Gas Powervalve





. Or drill and tap and plug with allen set screws.





















I hope I covered most/all of this

Also, if you look at my number # 1 cap, you can see it is shorter.


Others use the spring provided.




Note where I did not grind on my pipe. I used a blade screwdriver and popped the spring to wedge under the hump on the pipe. Holds every secure; over 3 years now.

Important Note: I can't give advice to where the red adjuster needs to be set at, everyone's motor is different. Instructions should also be provided with a new kit. RIVA Yamaha can also help provide assistance to obtain the factory original instructions.
I also do not recommend grinding on the OEM pipe as it is jacketed. Any grinding that is done, is done at your own risk.
Proper fitment of valve must be verified by user prior to assembly. The valve only goes in 1 way, please ensure the valve is properly installed prior to assembly or possible engine damage can occur.
These steps listed above is only a guideline and you are installing the item at your own risk.
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