Complete 657 Rebuild - Reglaze or bore? Crank options? Pics

[Jris88]

Hey all,

Finally split the case on my seized 657. Found that the PTO side rod bearing is shot. Rod has a lot of play on the shaft. Best option for a replacement crank? Was thinking about going with SBT.

As for the top end, the PTO piston had damage around the base and there was some scoring on the head cover. The cylinders look okay to me though, no deep gashes or scratches (see pics). Not too experienced rebuilding engines so looking for some insight given their condition - should I just reglaze the cylinders or send them out to be honed/bored oversized?

Lastly any top end kit recommendations? Would you go with Pro-X, Wiseco, Oem pistons?

Thanks!

 

[AKnarrowback]

You want to hone the cylinders and see if that clears up any scoring. Once they clean up they need to be measured to see if you need to bore them. If they need to be bored I always buy the pistons first and have them bored to match the specific piston.

If you can, specify that the crank you get has OEM inner seals. I had my local shop order a reman crank for my 657X and have leaking seals after three years with aftermarket junk, not a confidence builder.

There are others on this site that will chime in with very good advice on who to get a crank and pistons from. I have always used SPI pistons since my local shop carries them, I have a bunch of rebuilds on sleds and PWC's using them without any failures or problems.

 

[NickCawks]

On my 657 I got a crank from SBT. You will send them back yours as a core for a decent discount. Some on here will say not to go that path because they are welded but I've had no issues for the last 3 seasons with mine.

As far as the top end, if you can find a shop that does them locally that's your best bet. Pretty much all of the online services that do it are being reported as having very slow turn over time lately, and at least in my case the local shop was a good bit cheaper than sending it off to someone like full bore.

I'm not sure how common it is to find shops that specialize in jet skis, I know I was surprised when I found one near me. Still worth a look

 

[mikidymac]

So with Seadoo not selling cranks anymore you only have a few options. WSM or SBT for shipped cranks but best and most expensive is sending yours to CrankWorks.

You don’t have your cylinders coated because they aren’t Nickasil, just iron. Best pistons are OEM then probably Pro-X. Yours will definitely need to be bored oversized. Don’t trust anyone local unless they do a lot of 2-strokes. I send all my cylinders to Group K in Arizona.

 

[etemplet]

I got a 657 I am probably not going to build. The bottom end is together and it feels pretty good to me.. I don't think it is a 657X but it might be. I can give it a good once over if you are interested in it. Save you a lot of money and some work. Depending on if you want a new engine. How does $150 sound for the bottom end. Message me if you are interested. I don't generally sell parts.... I just got a pile of engines and building this engine would be plain silly for me. LOL

 

[Jris88]

Thanks everyone for the suggestions! I originally decided to buy an SBT crank and get my cylinders bored and new pistons from WSM (they’re local). Once I factored that cost, gasket kit, plus a new case (my rotary surface was toast), I was a few bucks short of an SBT rebuild with a year warranty. So I decided to go with SBT - will be delivered on Monday.

My rotary valve cover is bent and gouged so I will be replacing. Attached in the first pic is my rotary valve cover. I’m assuming this is no good due to that gouge?

I was looking on eBay and found one (picture 2) that looks okay.

Think I should pull the trigger on this one?

I read about the solder method, I will attempt that either way when the new engine/valve comes in.

As for next steps, plan to:
-drain fluids
-rebuild carbs
-replace fuel lines
-replace oil lines
-test oil pump
-replace wear ring

Any other things I should look at? Thanks guys!

 

[Jris88]

Well I decided to just go with SBT on the RV/cover as well. Only a few bucks more than ebay.

 

[etemplet]

Looks like you got i all covered. Depending on the model of the ski you might want to remove the fuel baffle and check it out. Make sure everything is clear and clean and.... test the fuel sender to make sure it is working. Nice to have a working fuel gauge. Goo Luck !!