My new to me project. 1997 spx 787

[Axkiker]

So I picked up my first ever pwc..... YEAH me!!!! Now here is the kicker, the motor came in a couple boxes LOL

After getting everything out and in the open it appears that someone didnt winterize correctly as one of the jugs was popped. The sleeve was fine but the outer waterjacket was cracked outward. I cant say for certain but it appears thats what happened. It came with 2 extra jugs which appear to have been recently machined to 82.45mm and honed. Neither appear to have been used as the cross hatch pattern is untouched.

The bottem end is still intack and doesnt appear to have been apart. Spins freely blah blah but I have no clue to its condition.

Curious as to what you all think I should do. I would love to just throw a top end kit on it and roll but im worried about the bottem end. Can you all give specs and methods to check without tearing it apart. Or would you all suggest tearing it down and checking for wear. What kit or piston type would you use on the top end. Seems like I have heard that once you go back 82.25mm you should use a specific piston kit.

I got this ski cheap so I really dont want to put a lot into it, then again I dont want to throw a rod out the side either.

Any specifics you can tell me about the spx or 787 engines. Seems like everything I have read thus far is good.

Another off topic question is does anyone have a good way to flip a ski in order to do bottem work? There are some gashes I would like to work on but am unsure how to flip it safely?

thanks!!!!

 

[Spimothy Leary]

1) tear it down, for SURE, you have no idea exactly how the crank looks w/o pulling it, and more importantly, if there is any debris.. ANY Debris in the crank case right now, thats a bad thing, you want it spotless inside there.

1b) to just 'check' it you really just turning it a few times and listening to the bearings,,, are they quiet and free spinning ? (but thats very much a half azzed approach) and frankly since your half apart now,,, no reason not to finish the job right, half the work has already been done.

1c) the only reason to not tear it down is if you plan on putting it together, riding it one time for about 5 minutes, then selling it to somebody you don't know or don't like... if its for personal use,, there is no reason to skip this step.

i don't know the cyl measurements in my head but generally speaking its silly to bore out cyl's w/o having the pistons in hand, you want a good clearance .006 to .0065, and the only way to be 100% sure on that is to have pistons in hand, then get the cyl's bored to match.. not the reverse...
so i'm not sure if those measurements match up properly with a piston (stock .25, .5, whatever)

 

[Axkiker]

Good info.... would you recommend to take the entire bottem end apart or just pull the bottem cover and clean and check. I guess im more accustom to working on cars where you can measure side play etc in your rods and crank to check things out.

I agree it is kind of backwards to have your cyls prior to pistons but thats what I got... Hopefully I can take some specific measurements and order pistons to match or hone the cyls too fit.

 

[Spimothy Leary]

my biggest concern is the bearings, not the rods, and of course the crank seals but there is really no way to say that the crank seals are a+ until later... i'd very much prefer to take everything out, look at the CB shaft rotary, etc, and look closely at the crank itself, bearings, blow out any possible debris, lube it up and go from there if it looks good. like I said your already dam near half way there... the only additional cost is gaskets $65.

and yes, if your bore is within the right tolerance, you might be able to get away with a .25 or .5 piston kit and get lucky, its quite possible.. just weird for someone to bore out a cyl w/o having the piston right there at least for the final bore.

do keep in mind, this is a pwc not a car,, your going to be running 5-7K rpm a LOT... not the case with a car, so IMO you can't be quite as flexible as you would with a standard sedan.

this is probably not a good analogy but you should basically treat this like a race car, not a 4 dr Taurus, those rpm are going to be hopping from 1500 to 7K on a regular basis, and getting bounced up down/left right and in the worst conditions possible, high moisture and heavy salt content, with open cooling not closed loop.

If it was me, it would be a complete teardown, inspection, blasting everything to bare metal, washing it about 6 times, then put it back together & paint when complete. (set some time aside )

 

[Axkiker]

Okay this may be a stupid question but these things do not use any typical babbet automotive style bearings do they. I have never had one apart and always assumed needle bearing were used for the wrist pins as well as the mains and crank ????

I assume that the needle bearings are inspected and if seem to be in good shape can be reused ?????

My cylinders appear to be slightly small at 82.45 mm. Im hoping I can order a .5 oversized piston and have the cyls honed to get within spec. I guess we shall see

 

[Spimothy Leary]

bah, now your getting over my head, a true wrencher would have to chime on that... I flip a few ski's a year, I'm the buyer and seller, and i'm really good at taking them apart, and i have a skilled mechanic/partner that puts them together, i'm the errand boy that runs to the machine shop for boring and i always take the prepped cyl's to the shop with the pistons for a proper job. if your close, the hone just might do the trick.

 

[brock1]

uses wrist pins...With the price you will pay for parts and time why dont you just get a used motor from one of the guys on here...pm 99spxxx and he will let you know if he or his bro have a motor....it will be the same price and what you are trying to do and less hassle....

 

[Axkiker]

uses wrist pins...With the price you will pay for parts and time why dont you just get a used motor from one of the guys on here...pm 99spxxx and he will let you know if he or his bro have a motor....it will be the same price and what you are trying to do and less hassle....

Ill check with him

 

[brock1]

ok i just got an engine from him for my xp it was a 720 and he was very reasonable with the price.... him and his brother are great to work with....if you cant get ahold of him pm me and ill give you his phone #

 

[Spimothy Leary]

i disagree, a motor will cost 700 minimum +shipping which is $100 min... (and maybe a core ?)

in this case, assuming crank is usable... he's looking at sub $300 shipped to the door for a piston kit, gaskets, and his time... actually sub $200.. i think i paid $170ish for a .5 piston/gasket kit shipped just a few weeks ago...

now if the engine is 'toast' then yes,, absolutely but if the crank/cb/cases are good, cyl's are usable 'as is" he's getting off cheap,, even if the cyl's need a new bore to match pistons,,, it only adds $100 to the job. still well under half the cost of an engine, and frankly you don't know the condition of your replacement engine, just that it had good compression,
if your doing a rebuilt,,, then $700 goes out the window, now its 1K and the rebuilder gets some really nice used parts, the only winner there is the rebuilder.

a LOT depends on the crank,,, if the crank is good, then replacing the motor makes no sense, if the crank if fugged... then the price gap is much closer and it depends then on the individual and their mechanical expertise... quite a few could do a straight engine swap,,, quite a few less can do a complete tear down and rebuild...

and i'm not saying a good used motor won't do the job, but its still an 'unknown' no matter how good the compression numbers come in, my xp was 150/150 when i bought it,, and i assure you it would NOT have survived the first hour on the water it was so disgustingly dirty inside... the only thing that saved my crank & pistons was a complete tear down.

 

[brock1]

paid way less than that for my engine from 99spxxx ......he has almost no money into the ski at this point so a 600 dollar shipped engine would give me more security than rebuilding one that i dont know the reason it failed in the first place...maybe its my thinking but a cheap ski is worth putting money into if you are going to have it for a long time

 

[Spimothy Leary]

paid way less than that for my engine from 99spxxx ......he has almost no money into the ski at this point so a 600 dollar shipped engine would give me more security than rebuilding one that i dont know the reason it failed in the first place...maybe its my thinking but a cheap ski is worth putting money into if you are going to have it for a long time

in that case I stand corrected... $600 shipped is pretty dam cheap. although granted it still has 'unknowns' where rebulding your own motor has no 'unknowns" but i've never seen one $600 shipped, even locally here i've never seen a running 787 for less than $600 picked up...

however, if I could get a running 787 shipped for 6bills with any form of a guarantee (makes it thru first day), i'd probably do it, and sell my cases, crank, cyl's, cb shaft, head for about $450 and it would only cost $150...

and dont' get me wrong,, i'm not suggesting cutting corners to save money, i'm actually suggesting cutting NO corners, still saving money, and making sure its 100%...(by cutting no corners you are assured that you have an engine thats ready to rock)

however a lower price point of sub $600 shipped does narrow that gap significantly... i'm still shocked that you can get one that cheap.

 

[Axkiker]

Looks like a lot is gonna depend on me pulling the bottom end apart and checking it out.

Provided the crank looks okay who would you suggest to buy a kit from ???? Not looking for race parts, just some descent quality stuff.

thanks

 

[Spimothy Leary]

i've bought multiple sets of 787 platinum wsm's from jkwatercraftparts on fleabay.

 

[Strizzo]

The bearings are not automotive style that you'll find in a car engine, the are all roller needle bearings on the big end, wrist pin and throughout the driveline.

 

[Axkiker]

Can someone tell me where the MPEM is located? I have not searched for it to see what kind of shape it may be in and would like to do that tonight.

thanks

 

[Jimnut]

MPEM is located in the gray electrical box on the left side of the gas tank


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[Axkiker]

MPEM is located in the gray electrical box on the left side of the gas tank



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Okay I assume you mean left as if you were looking at the ski from the rear ????? I think I remember seeing it when I was poking my head around in there.

thanks

 

[Spimothy Leary]

Okay I assume you mean left as if you were looking at the ski from the rear ????? I think I remember seeing it when I was poking my head around in there.

thanks

yes, left from the rear... the port side
yes, its a funky shaped grey box... you should be able to see it easily will look like this (top middle of pic) it won't be in the exact same spot as mine, i had to move mine back when I put in the larger gas tank, and the box is easily removable, two clips, pop & lift, it sits inside a bracket.

 

[Axkiker]

Yeah I think I remember seeing it. The only thing is that I only remember seeing 1 wire coming out of it. !@#$@$@#

 

[Axkiker]

Yeah I think I remember seeing it. The only thing is that I only remember seeing 1 wire coming out of it. !@#$@$@#

Okay I was able to look tonight and found it. Looks as if I have 3 different ports coming out of it with an additional 3 not used. Guess I will have to wait until the motor is back in to see if its good. Which sucks

 

[Axkiker]

Okay so I was finally able to get the bottom end apart and have to say im happy that I did. Thanks to all who made that suggestion. There was nothing real alarming in there but there was some gunk etc in the bottom which I am happy to get out.

/all bearings etc seem to be in good shape. All spin freely with no noticeable hangups or signs of being bad. The only thing that struck me as strange is a couple bearings seemed to spin just a little easier than the others. They all had about the same about of play but these 2 acted like they were a little more free. Almost was if the rest had some lube in them but these 2 didnt have any or as much. Anyways from what I have seen the bottom end is good to go unless someone here says different.

Now this may be a silly question but is there a way to get the crank apart. This is my first attempt to rebuild this style motor and didnt think about the crank being pressed around the bearings. The seals which I am unable to remove without pulling the crank apart seem to be in good shape however if possible I would still like to replace. Im guessing that im out of luck.

any hints ??

thanks

 

[Spimothy Leary]

glad you inspected it.. and that's the reason I said it was important... that 'gunk' can kill an engine in no time....

do not take the crank apart !

i repeat ... do NOT !

just clean it up... and clean up the crankcase real good,,, and I mean real good.

 

[Axkiker]

glad you inspected it.. and that's the reason I said it was important... that 'gunk' can kill an engine in no time....

do not take the crank apart !

i repeat ... do NOT !


just clean it up... and clean up the crankcase real good,,, and I mean real good.

Okay Okay.... I will resist the urge... lol...

So is there no way to replace those seals in the middle of the crank ????? I assume not which makes me sad.

They seem to be in good shape but hey while im there I would rather replace everything possible.

 

[Spimothy Leary]

if they are in good shape, leave them be...

there is always a way... but that's why guys make a good living as rebuilders... not for us

for your average guy, the only thing you can really do on the crank is outer bearings, and you'd need a press and some experience, the rest, don't mess with., be happy they look good but you won't know if you have leaky crank seals until you do a leak test (and no i can't tell you how to do that, my buddy knows, i leave complicated stuff to experienced wrenchers) but there is a way to do it b4 the engine gets dropped in, involves hanging the short block and running oil to it, yada yada.

Be optimistic that they don't leak if they look good thats all you can do, or search on how to do a leak down test, its probably out there.

bottom line, it appears that doing a complete tear down was a good idea, you likely saved a huge hassle (engine failure) by NOT skipping that step.

also, that's the reason why replacing your engine with a "good used motor" is sometimes a bad idea, since there may be issues with the crank that won't show themselves until its too late.

the good news is that when this all goes back together, you'll have reasonable assurance that all your parts are in good shape and ready to run !