787 top end

[DAGRE147]

Will be looking to rebuild the top end of my 98 speedsters starboard engine. I'm familiar with pretty much every aspect of a 2 stroke seadoo except the actual cracking open of the motor, so imma lean heavily on you fellas for a step by step as to how to accomplish it. I was gonna grab a donor ski motor for cheap off craigslist but I've convinced myself that sooner or later imma have to gain this knowledge so why not now?

I should be back stateside in about a month, so I can start ordering what I can now. Suggestions?

Pic of the trashed top end :

 

[Sloanman7]

if your gonna take the time to pull the motor i woundnt just put a donor in and call it good. just make it a winter project.send cylinders off to get bored and a new pistion set. grab a oem gaskets.maybe a new crank. your obviously your gonna need a good used head. its not real hard if your a good shadetree mechanic. lots of info on here to help. and if your not comfortable with a rebuild, SBT is a option. but my first question befoer you decide on anything is, what is the cause of the engine melt down? you need to investigate what cause this to happen. or you may have done a rebuilt just to have it fail again.

 

[CReynoldsMIZ]

looks like water ingestion to me with all that rust in one cylinder. also looks like that isn't original top end, I cant make it out if it says it has been bored .25 or .75 over already.

 

[Matt Braley]

I know that engine and a non mechanic guy and his roommates took a stab at it unsuccessfully. I was given that other 75 over piston in the box with the other "extras" the guy gave me.

The engine is locked right? I've got a feeling those crank bearings are gonna be as rusty as that OEM cylinder is. You can still do it but it may take more then a top end.

 

[DAGRE147]

Locked up pretty tight, it had some play but I didn't wanna gouge the cylinder walls by forcing anything. I guess my next question is what could I order now with what little knowledge we have to go off of.

If they are already bored .75 over, what's the next safe bore? I guess just a hone is out of the question right now lol also ordering a top end in advance

Any special tools I might need? Trying to order it while I'm deployed bc the wife tends to let that stuff slide when I'm overseas hehehe

 

[doomann88]

First thing is to look at any scoring and make the best guess as to how much bigger you need to bore out the cylinder to remove the damage. Then buy an accordingly sized piston. The piston needs to be measured with a micrometer to see exactly the final bore size for the specific piston (they are all not exactly identical) based on the specs in the manual.

 

[Matt Braley]

Tear it down first then your not guessing about anything. If you want to bore it I'll trade you that already bored cylinder for one that has not been bored yet. I have new OEM .25 over pistons in the box cheaper then you can find anywhere.

I have the flywheel puller and a pto puller. If you bring the engine over we can pull it down in 15 minutes with the air tools.

Here is what I have locally so you can bounce it off whatever else you can find.

Non OEM rebuilt crank with seals $300
OEM first over pistons $85 each
Good used counter balancer $75

I'm happy to help for free no matter where you find the parts. I still have pieces of your alignment tool I need to get back to you. We are looking at doing a Florida ride in November, hope you can come.

 

[CReynoldsMIZ]

dude at this point, why even bother with this engine. either find a used reman or I would send it off for a warranty. Matt's prices are good, but you are looking at 500 bucks for a crank, pistons, and counter balancer. that doesn't include the $50 head you need because your's is tattered up, doesn't include boring they cylinders/finding new ones. I mean your getting close to $700 without gaskets.

You live in florida, why not hit up SBT? I just think for an extra $100 or $200 you have a clean engine put together in a factory with a 2 year warranty... No warranty on your own work.

 

[wfo speedracer]

I would take an engine that Matt rebuilt over an SBT engine any day of the week, that's just my opinion.

 

[glsmohio]

Tear it down first then your not guessing about anything. If you want to bore it I'll trade you that already bored cylinder for one that has not been bored yet. I have new OEM .25 over pistons in the box cheaper then you can find anywhere.

I have the flywheel puller and a pto puller. If you bring the engine over we can pull it down in 15 minutes with the air tools.

Here is what I have locally so you can bounce it off whatever else you can find.

Non OEM rebuilt crank with seals $300
OEM first over pistons $85 each
Good used counter balancer $75

I'm happy to help for free no matter where you find the parts. I still have pieces of your alignment tool I need to get back to you. We are looking at doing a Florida ride in November, hope you can come.

Im in the same boat. I would go with Matt over ses or sbt or full bore. You know the work will be done right. Lets face is most of us on here are hear to learn and have fun. You would learn so much with Matt helping you out and in the end you know it will run. Your also getting way batter parts with Matt. Another thing. even if Matts parts where the same as a reman I would still use Matt. He has helped every person out one way or another on here and never asked for a dime (yes i know there are other people on here the same way) Just my 2 cents.....