Just purchased 2000 Seadoo GTX RFI 787 for $350-need help!

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Start from the middle and work diagonally 1/4 turn at a time 2 or 3 times and then once they are all loose you can take them out.

I find that after cracking a few loose they become tight again as the next set are loosened. So just take it a bit at a time and you'll find after a bit they all feel free.

Its pretty straight forward.


BUT before you start I'd recommend grabbing the crank and setting the piston's at equal heights. This will block the transfer ports and anything you drop in the cylinder will not go anywhere.

FYI when your re-installing a head: Its grease on the threads of the bolt and blue locktite under the head. Sometimes the manual can be confusing about that part but this will make taking them out easyer next time. Also there is a two stage torquing procedure. First time torque to 9 ft lbs and then up to 17 ft lbs for the final. Mainly your just squishing down the gaskets in small amounts before really pushing the head down.
 
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This is a little more work, but you can pull out the rave valves and look right at the side of the pistons and rings. Pop the covers off, unscrew the caps, then pull the two bolts on each one. Then you can pull out the rave valves. Then look in the slot with you flashlight. Turn the motor over by hand and look at the rings and piston skirt. Take pictures and post if you can. You need to pull the raves anyway to clean them so this is a good time to do it.
 
Also, you can take off the carbs to peek through the rotary valve openings. :-D
This is what I did. But not just for peeking.


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Yep, I answered my own question. I had .045"! I fixed it..

Carbs?? What carbs?? (Can't pull out what you didn't have)

Ok, so at this point I will need rings, new piston, and new head possibly (although I think it can be cleaned up)
Where do I buy my stuff?
Man, ebay has TONS of heads on there that are all messed up! This must be a common thing huh? What happens? Does it suck up a shell or rock into the cylinder?
What about that small scratch in the wall? Should I buy a new one or is it not that bad?
Questions, questions but I am happy to know that was probably my issue there.
I am a little concerned that there may be bits and pieces of metal down in the block! Wish I could clean that out someway.
 
Lol like I said, this is how it starts :P

You can find part's here from our valued members, or Ebay, WSM, OEM, lots of options.

If it was me I would pull both cylinders off. Bore them to the next size that takes care of the scratch. WSM platinum is what I'm used to using. They come in 82.25, 82.5, 82.75, 83mm... sizes. but If yours are 81.89mm that mean's they are stock size and could just go to the next size that clean's up the cylinders.

Their top end "kits" come with all gaskets, pistons and bearings. BE CAREFULL removing the piston pins' the bearings in there are not caged and as soon as the pin moves out of the way, all of those needle bearings drop into the base which sucks :P but the new kits come with caged bearings.

When you said "heads" earlier that sounded like you mean that you have a performance head.
There are performance heads that have two removable domes that can be changed. But going by your pic's you have a normal stock head and the other part is just the head cover. You can replace or clean the head.



How much of the ring is missing ?

IF your didn't collect all the pieces its possible that there are bits left in the bottom end. You could vacuume it out and take a chance or take the engine out and take the bottom end apart to be sure.


But then again the top end kit is around 250$ and you could get away with just that as long as there isn't something else that you don't know about.

On the other hand if a piece fell down the oil hole which leads to the bearings... you can only remove it by disassemble.

The dilemma in that case is: Rebuild or replace...

A new engine is 800-+ a bit. Once you start tearing into the bottom end you will be thinking, (250$ top end 400$ crankshaft, seal's, gaskets...) Its not hard to just go for the rebuild but the engine rebuilders offer a 2 year waranty which is very apealing.
So if you have a problem and maybe find a bad injector and it fries the motor you will get another one under waranty.

If you were in canada I'd be preaching to rebuild but in the states, a replacement is a no brainer with free shipping and waranty. Its 1200$+ here + shipping from montreal without waranty unless installed by a dealer which is another big expense.:(
 
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Wow Mechanix!! Big help man!!
At this point, I think I will get a WSM Platinum kit for about $180, new head cover (which has the squish area-not sure what it is called) and have both heads bored out to next next size up. I'm a little confused as to what size kit I buy though. It comes with pre-gapped rings in that specific size? Like if I order a .080 kit it comes with new pistons, gaskets, and rings that will match my .080 heads I get back?
I'll pull the rave valves out and get a mini flashlight to drop down in there and see if there is anything down there. Don't want to take the motor out of the ski or take the bottom end apart at all.
I'll pull the heads, then pull the pistons out and see if I can run a magnet down there to catch any metal pieces-in fact, I'll count how many pieces broke off the rings and that might get me closer to how much crap is still in the motor.
Mechanix, THANKS for the tip on the needle bearings! I would've certainly dropped that shit down into the motor! Haha!
In fact, how much scoring is too much? The mag side has a very slight scratch I can feel with my fingernail but the other cylinder is fine. If I can get away with just replacing the pistons/rings quench area I would be super happy with that!!!
 
The kits come come with piston's and rings set for lets say 82.5mm. That means you need to bore 0.5mm more or 20 thou over. Allow for 4 thou clearance and the rings are gaped for that final size according to their instructions but their instructions are a little different than OEM.
Its hard to say what kit you will need but it depends on the scratch. If 0.25mm will take care of that, great! But that means you have to devide that number by two to know how much will be taken out of the wall all around. So if 0.125mm is enough to get rid of the scratch then its good. If not there is the 0.5mm kit that will surely do but best bet is to take the cylinder off and have a machinist look at it to be sure. A scratch that you can catch with you nail usually means that just a hone won't be good enough.
The other thing to be careful of before removing the cylinders is to vacuum the sand, rocks and water from the bottom of the cylinder water jackets near the bolts. That way when you pull the cylinders off, that stuff won't fall into the bottom end. Also there is a tube joining the cylinders in the back behind the cylinders and that is the lower drain for them. Its a pain to get them off with the pipe and cylinders in the way. The other option is to pull both at the same time and deal with the ripping gasket and possible things falling into the base. Do a google search for that year, make , model and the word shop manual and you can download them. That will show you what's inside the motor and what to expect.

But once your go to an 82.5mm kit. you need to clearance the rave valves. ( under the black cap's ) they are very close to the piston. If you bore too big the piston can hit the valve. So if you bore to 82.5mm Just take .25mm off of the rave valves and it will be back to stock clearance. The actual spec is in the manual, I can't remember what it was. Its easy to do yourself or have the machinist do that too. Also really important is to chamfer the ports so it doesn't snag a ring in the port.
 
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Okay, that ish was over my head. Too much math for me. Haha.
I read about the rave valves and grinding some off if you go with a larger bore and it kinda scared me.
I also read about ring gap tolerance and to stagger the rings and also make sure the opening of the rings don't go over the intake or exhaust ports.
Pulling the heads seemed easy at first but when you mentioned that tube that joins the cylinders I might have to check into that too. Wow, you are a wealth of info man!
Okay, those rave valves...when I unclipped the spring and popped the top off with the spring there is a cap that unscrews. Does that have to be a certain torque? I mean does it control fuel pressure or air pressure and has to be a certain torque? Just wondering.
Man the "top cover" had ALOT of calcification under it.. A bunch of white powdery crap all over the place...
I guess I'll just put it in the blast cabinet and clean it that way? It was bad.
What are all those rave valves for? They are all over the place!
 
The raves basically lower the exhaust port. That means your piston has to travel further down before it can let out the burning exhaust. That means that: since the piston has to travel so much farther that you get more power for a longer amount of time.
So its acting like you have a really long stroke engine. But those engines will not have any top end power and they run out of steam soon so to speak.

After you hit a certain RPM or exhaust pressure. The raves start to move out of the way because of the pressure pushing against those bellows lift's them up. Now that the raves are out of the way that means the port is shorter than it was and the piston has a shorter stroke before it lets the smoke out :P
This is important for having top end power.
I'm not sure if there is a torque on them I simply stop when they are snug because it is just plastic. So maybe 30-50 inch pounds. Ill see if its in the manual.

Essentially the raves give you low end power and move out of the way to give you top end power. In order to do that they have to be really close to the piston so that they act like they are part of the cylinder's port. Otherwise the if the gap is too big then you will loose some low end power as the exhaust escapes around them.


Taking that line off the back of the cylinders is a pain but is possible. Just might have to do it blind. Cutting the zip ties is the hardest part :P

Careful with the top cover. Stay away from the outer seal edges while your blasting.

There is another rave on the exhaust can but its not an actual rave. It just looks like one because of how it works. Its actually a water regulator. It takes water coming from the cooling system and either sends it into the pipe when your cruising around at low RPM's and in higher RPM's it sends water mostly into the can.
It has two purposes.
1 to cool the exhaust.
2 by injecting water in the pipe at lower speeds it cools the exhaust and slow's down the pressure wave in the exhaust pipe which means that you get better low end power and you get more power at top end when there is less water flow. Its cotroled based on exhaust pressure somewhat like how the raves work but all its dooing is controlling how much water goes into the exhaust pipe versus how much is going into the exhaust can.

All three rave look alike parts are for performance compromising. Meaning they manage things at low RPM's and do help quite a bit but they get out of the way at higher RPM's and allow the engine to breath and perform better.
 
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The math is pretty easy.

Stock is 81.89mm.
Bombardier offer 82.15 and 82.25mm. That's it! WSM offer more oversizes and there are others that offer more beyond that.

But lets say your bore was 82mm and you got an 82.5mm kit.

That means the new kit is 0.5mm bigger in diameter straight across.

That means you will have half of that number worth of material taken out of the cylinder all the way around.

So if that scratch is less than 0.5mm/2 or 0.25mm than it takes care of your problem.

That also means you can take 1/4 of a milimiter off of the raves. I can't even imagine how small that is. :P

What I do is take the new piston and some 400 grit sand paper and put it around the piston. Then I take the rave and use the piston with the paper to sand down the rave edge.

Then I Re-install the rave and check the clearance between piston and rave while the piston is in the cylinder with the rings installed and just slightly above the rave valve port.


Also you meansioned about piston ring alignment. Well there are pin's on the piston's so it doesn't mater. They only have one place to go. Oh and the Leter on the rings are messed up. The top right is printed on the bottom of the ring because of its shape. The reason I mension this is because it fooled me once. I had the top ring on the and the leter was on the bottom so I thought the bottom ring had to have the leter facing down too. I was wrong. sort of. The bottom ring is Square so it cannot be put on upside down and in this case the letters don't mater at all. But convention is to have the leters facing up in most other applications.
 
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Damn that was a lot of work took me three hours just to get this far....
10 points to the winner of what's wrong in this picture.....

What the hell happened here????


Look at all the metal pieces in the bottom!!!
 
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Ohhhhh yeah!!!!
ALOT of play! I pulled the motor tonight. It sitting on the floor at the moment.
Well, at least I know all of the electronics are okay. I mean, it DID start for about 10 seconds.....lol
Damn, wonder if I should just sell it to my uncle or go ahead a crack this thing open. He said he would give me $500 for it for pain and suffering:)
I'll have to price out bearings, piston, jug, rings, and possibly the top of the cylinder head.
 
Send it to ses, less than a grand and you have a killer ski for under 1500!!
I did the top end on my 787 gsx but if I needed a bottom end I knew I would just do an ses rebuild.


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There's a guy in PA on eBay that sells a complete motor for $700 shipped!
He boasts that it has better oiling capabilities than stock because the rods are better and have oil holes to help out.
Thought about it. Not sure at this point. Gonna be Into it for about $1500 when its all said and done. Didn't wanna spend that much.
 
Jp6940 said:
There's a guy in PA on eBay that sells a complete motor for $700 shipped!
He boasts that it has better oiling capabilities than stock because the rods are better and have oil holes to help out.
Thought about it. Not sure at this point. Gonna be Into it for about $1500 when its all said and done. Didn't wanna spend that much.
Click to expand...

When you spend that $700, she becomes your toy, and when it becomes YOURS, more $$$ pouring in, and you would be wondering: "hey, who said $1500! definitely not me!" LoL
 
That's the same guy on eBay. He has $999 on his site but $699 on eBay.
Looks like a badass motor and unlimited warranty!?
I don't know what to do at this point. Lol
 
Davidgsx said:
I tell my wife every single project I get is $100, and I always have 2 or 3 going!! You would think at some point she would call bullshit on the mere fact that it's always " 100 bucks honey"


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Click to expand...

At first I used to fib but after like 10 successful projects in a row she doesn't ask and I don't tell unless its a super bargain. My wife has only one rule when it comes to projects. "when I get home from work I want to park in the garage" there are no other rules. (and I break that one occasionally but generally no more than 2 days a month)
 
Spimothy Leary said:
At first I used to fib but after like 10 successful projects in a row she doesn't ask and I don't tell unless its a super bargain. My wife has only one rule when it comes to projects. "when I get home from work I want to park in the garage" there are no other rules. (and I break that one occasionally but generally no more than 2 days a month)
Click to expand...

She gets to do what she wants in the house, the garage is mine! Honestly shewouldn't say much if I told her the exact numbers just find it's less headache this way!
I make a lot of side cash on my motorcycle rebuilds and I'll often hand her 3 or 4k to go spend so she gets super happy and gives me my garage time!
Here's a shot of my last rebuild, I don't have a still shot on my phone but it came out pretty cool, I made away with 5k on that one
169.jpg



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Davidgsx said:
She gets to do what she wants in the house, the garage is mine! Honestly shewouldn't say much if I told her the exact numbers just find it's less headache this way!
I make a lot of side cash on my motorcycle rebuilds and I'll often hand her 3 or 4k to go spend so she gets super happy and gives me my garage time!
Here's a shot of my last rebuild, I don't have a still shot on my phone but it came out pretty cool, I made away with 5k on that one
169.jpg



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Click to expand...

Wife is happy, life is happy :-)


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