94 Sea Doo XP Crankshaft/Engine Question

[Surovich]

Hello,

My wifes cranksahft went last year in her 94 SeaDoo XP - So I bought one used from a 650 Engine (Looks identical) except for the parts that connect to the pistons - was there two model crankshafts for that year? If I get correct pistons will I be fine?

[Technical Support]

There is only one 657 crank. What exactly is different?

[Surovich]

I have a friend rebuilding the engine - I will have to ask for more specifics ... Thanks again for the always quick reply. If there was just one, maybe the guy who sold the other to me wa mistaken on the engine model (great, since its almost brand new - Ill have no use for it... guess Ill have to ebay it)

[Surovich]

Ok, I finally got some pictures and I had a mistake in what I was saying - The Crankshafts are identical except for where the rod from the pistons connect to the crankshaft. On the original shaft The pistons in the picture fit (Although they are too big for the case) but that same rod is too big for my good shaft. Hmmm, Is there a way to attach pictures? I Dont have a location to store em.

[1fastski.com]

there is 2 657 cranks . the 657 and 657x the x crank has a bigger wrist pin end .

[Surovich]

Ah, That answers the crankshaft question - Now with that said - Can I use a 657 in place of a 657x. Of course I will need new pistons, what type would I need and what size for a 657 engine?

[Technical Support]

Sorry, I see what you are saying, now.

We use the same rods and bearings for both the 657 and 657X, I'm not sure what you would need differently if you are going OEM.

[1fastski.com]

you will need the pistons and bearings that go with that crank , also the rotory cover is differnt from 657 to 657x i have seen many mismatch the parts but you will loose performance , also if the timming is not right you will toast the motor .

[Surovich]

Hmm ... Since its 94 I want to get it running as cheap as possible [img]smile.gif[/img] - So I could use the crank with the correct pistons, Do you have any specs on the pistons that would be needed for a 94 case and 657 (not the X) crankshaft? I dont want oversized. (SBT have them by chance?)

Or do you guys know anoyone that will take a perfect shape 657 crankshaft and fix my broken side of my 657x crankshaft as a trade?

Thanks!
Scott

[Technical Support]

Your cheapest bet is to get a used 657X crank, since it's the part that fits the engine and parts you have.

[Surovich]

Hey, I also forgot to ask - One side of my head cylinder has pits in it - I dont think they are too bad, should I replace that or is it fine to put back on? I know new they are 200+ .

[Surovich]

Yeah, I cant seem to find a working used crank ... Might be stuck getting a rebuild and putting the 657 on ebay.

[Technical Support]

You cannot run a pitted head, they will create hot spots.

[1fastski.com]

i have a good head if you need , if your is not bad you could fix it but dont leave any pits in it . 75 bucks shiped if ya want the good head .

[Surovich]

I may take you up on that - Mine isnt bad at all, but I dont have the equipment to "fix" it. Im batting around a new motor idea and parting my good parts out like the new crank, crankcase, etc ... to cover cost. I would get one from SBT but the engine is already all apart :(

At this point, I would need a crank rebuild = $300, new head $75, Pistons = $150 (or so), and I have one more part that is shot (dont know name, but I can find that) probably like $100. If I could use this 657 crank, thats not bad - but if I cant I have to make a decision.