Need help with jetting 1997 gsx with r&d power plenum

[hunter_kramer]

I been working on a 97 gsx just did a full engine rebuild and was moving on to the carbs and noticed the needles were leaking so I figured I would a carb rejet for this power plenum I have laying around while I’m buying parts anyway. The ski is 100% stock. What do I need to buy and what will my mixture screws need to be set at for this job.Tia

 

[PorknBeans]

The '97 GSX has the 782cc engine with 110hp in stock form.

I ran my '96 GSX with a stock engine and an R&D Plenum and rejected carbs.

You'll only need to rejet(change) the Pilot jet from a 70(stock) to a 75 size. I don't recall the carb screw adjustments though. I'm thinking whatever stock settings are. Adding the free flow plenum and you'll neee to open the screws a little bit more.

 

[hunter_kramer]

The '97 GSX has the 782cc engine with 110hp in stock form.

I ran my '96 GSX with a stock engine and an R&D Plenum and rejected carbs.

You'll only need to rejet(change) the Pilot jet from a 70(stock) to a 75 size. I don't recall the carb screw adjustments though. I'm thinking whatever stock settings are. Adding the free flow plenum and you'll neee to open the screws a little bit more.

Would I need to open the high speeds at all? How much do you think I would need to open the low speeds?

 

[PorknBeans]

Looking at the carb specs for OEM carbs on your model. It shows the Low Speed screws opened to 1 full turn out; Highs - MAG(front carb) opened to 0(zero turns out) & PTO - 1/2 turn out

So to be safe...always tune your carbs to be on the rich side to avoid engine damage and then tune from there for a crisp throttle response when the throttle is snapped open.

A safe bet would be Lows at 1 1/4 and Highs-MAG 1/4 PTO 3/4. Then tune from this point by closing the Low Speed screws by 1/8 turns and checking the throttle response. Once the Lows are dialed in. Tune the Highs by 1/8 turns in. Understand these fuel circuits overlap. So fine tuning here is a must.

'97 Sea Doo GSX 782 motor
https://www.seadoosource.com/carbreference.html

 

[mikidymac]

With an aftermarket flame arrestor you will have to change the pop-off as there is much less vacuum signal than the stock one. You will probably have to change the jetting also, it isn't going to be as easy as turning a couple screws.

 

[hunter_kramer]

With an aftermarket flame arrestor you will have to change the pop-off as there is much less vacuum signal than the stock one. You will probably have to change the jetting also, it isn't going to be as easy as turning a couple screws.

I figure I would need different jets,needles and springs but I can’t find any info on what jets I would need or what the specs for the needles need to be.

 

[mikidymac]

Member @Matt Braley is the guru here on that so hopefully he will check in. You might try sending him a PM also.

 

[hunter_kramer]

Member @Matt Braley is the guru here on that so hopefully he will check in. You might try sending him a PM also.

thanks I shoot him a message

 

[PorknBeans]

Can you post a photo of the R&D Power Plenum?

 

[hunter_kramer]

Can you post a photo of the R&D Power Plenum?

 

[1of500]

Unless you are adding a pipe keep the stock air box

 

[PorknBeans]

That is the exact flame arrestor I used on my '96 GSX 800. I also had an R&D Recreation head(rec head) with 175 lbs. compression.

I removed the OEM 70 Pilot jet and installed a 75 Pilot jet with no carb adjustments. I worked with Chris Marrone of WaterCraft Magic when I did these mods. Had good bottom end and midrange acceleration over the stock set up and made my ski real fun to ride. Was more lively on spirited runs. I also used the stock carb brace. Which attaches to those two tabs with the holes in them. One year later, I entered the racing world and had removed this set up and went with bigger ticket items. Some which I still use to this day and are currently on this ski for surf riding and wave jumping in the ocean.

 

[POPPS]

Start with the oversize 75 pilots,,at 1 turn out,,,and see if it has a lean bog out of the hole, or needs to clear itself out. .If you have a lean bog and can't correct it at 1 1/2 yurns iut, then drop the popoff 5 or so,psi,,, I usually also start with the high speeds at 1 turn out,,,and then just read my plugs,,,better to start rich,,dark brown,,,and slowly turn in 1/8 of a turn to get the colour of a good ale.,,nothing lighter unless you are havasu world finals.