657x rebuild upgrades

[KGVD]

Help I have just recently had my 95 Spx blow up the pto cylinder and need to rebuild want to ask the forums for any suggestions and or help with possible upgrades for this engine I have trouble finding anything for this engine?
If possible please let me know of any options anyone has found to be a good upgrade

 

[mikidymac]

Really not any good performance options for that on. It’s actually a pretty peppy engine so I would just enjoy it as as.

 

[KGVD]

So I have seen unfortunately

 

[Don 94 seadoo xp 657 pair]

One of mine has the timing advanced, higher compression-I believe they milled the jugs down, larger jets, no screen in air box and runs 52mph in ideal conditions the one time I was able to look at my phone gps while riding it. I believe it has a different impeller too. Runs on quarter 110 octane 3/4 89 octane gas blend. Came that way, had a stack of receipts with it when I bought it, over $2100 in engine rebuild and work. I bought them both not running, cleaned the carbs and one ran fine, one terrible. After looking at the receipts I got 5 gallons of race gas and tried it in there, it ran great. So I messed the mixture and a quarter race gas works in it.

 

[KGVD]

Huh not sure what to do I seen SBT has the rebuilt top end at $495 bored 1 over and or I find a shop to bore locally buy the complete kit set and get done this year

 

[KGVD]

Just a question but can I just use all the existing parts and buy a rebuilt 720

 

[KGVD]

So I have taken the head off and found that the pistons and cylinder is in great shape but when I turn over the engine by hand there is a clunky sound in the bottom end is this the bearings?

 

[KGVD]

Any idea

 

[mikidymac]

Either the crank or rotary valve and or gear is locked up.
In rare cases it can be the pump.

To swap the 720 you would need different electronics and I’m pretty sure the carbs and exhaust are different too.

Basically if you want a bigger engine it’s easier and cheaper to just buy a new ski with a bigger engine.

 

[KGVD]

Thank you