Baffled speed quirk after. Wear ring replacement.

[etemplet]

Pretty sure the bore is stock. Previous owner did not say it was modified or rebuilt. Don't know a way to tell for sure without taking it a part. I could try and get a hold of him to ask but that may not be possible. I do remember him saying he had worked as a Seadoo tech and had replaced the fuel lines and rebuilt the carbs with mikuni parts. I will try and get a hold of him to ask but that may not be possible.
Will check the carbs and water control valve as you said.

Difficult to believe an engine that age has a stock cylinder bore. You can look down the spark plug hole sometimes and see the top of the piston or looking down the rave slot. I wouldn't trust asking someone. Verification is critical.

I have a number of old cylinders and pistons (different bore sizes) which I use at times to fit the rave valves. As long as I know the bore size I'm confident it will work properly.

 

[Waterdog59]

So tell me what to look for to verify the bore size? I agree got hold of previous owner and he did not recall changing pistons and bore size, but he bought it used so........

 

[Waterdog59]

Could I measure the existing rave valves and make sure the new valves would match?

 

[etemplet]

Could I measure the existing rave valves and make sure the new valves would match?

I am a machinist by trade and I can't think of a way to do that accurately and consistently without gauging it by the slide/piston clearance. Problem is the measurement is an "arc" and the measurement is constantly changing as it progresses.

 

[Waterdog59]

I am a machinist by trade and I can't think of a way to do that accurately and consistently without gauging it by the slide/piston clearance. Problem is the measurement is an "arc" and the measurement is constantly changing as it progresses.

Once the RPM drops the ski will not accelerate. I'd check the carbs as I mentioned and also the water control valve on the exhaust can for leaks. Just remember when you replace the raves if the cylinder has been bored out you'll have to file the raves to give the proper clearance. It can be tedious but my wife's ski hauled azz after I addressed the issues.

If the bore is not stock please explain the procedure for verifying the size. What would I be looking for and how to measure? Also please explain how I go about filing the raves and how to measure how much I have taken off. I am not a machinist so excuse my ignorance.

 

[etemplet]

Piston size is written on the tops of the pistons. It's not always easy to see. You can look down the spark plug hole with the raves removed it is easier to see but carbon buildup can make identification difficult. It may read "STD" or (.50) which is 1/2mm or (.020") also .75mm and 1mm. With (.25mm) you can get away with "not" fitting the raves but... I'd always fit the raves.

Think of it this way... IF the rave had (.015") clearance and you bore the cylinder out to (.25mm) which is (.010") then the rave would be (.005") closer to the piston. So you lose (.005") clearance. If you bore the cylinder to (.5mm) You will lose (.010") clearance which puts the rave dangerously close to the piston. So... we have to file the rave to keep a safe distance from the piston. I go (.020") because I don't want to train wreck on my engines.

I use a coarse 1/2 round file (10" long) to do the filing. I put the rave in a vice. My reference is the thickness of the bottom of the wedge on the rave. If I keep that wedge width the same size then I'm taking the same amount of material off. It's not a perfect system but that is why we measure in the cylinder bore with a feeler gauge. It works for me. Hope this helps.

 

[WhiskeyD]

There was a TSB released for the defective 1997 RAVE housings. They need to replaced with 96 or 98+ housings.