Rebuilding a 657 Rotax

[scarface]

Hi All,

Let me just start off by saying I am new to the forum and I am new to PWC's as well, thanks for having me and I hope I can learn something from those who have been there.

I just purchased a 94 Seadoo XP with a blown 657 - I knew when I bought it that I was going to have an interesting time rebuilding it because I have never rebuilt a seadoo engine before but as luck would have it I bought the factory repair manuel with the ski so I know all my torque specs, etc.

The reason I am posting here is because seeing how this is the first time I have torn down this motor type I would like to know if there are any 'known' issues that I should look out for or tips and tricks that I should know before I continue.
Right now I have the motor out of the hull and on my work bench, carbs off (rebuild kit on route) and exhaust manifold off. The head and cylinders are off as well as the starter, I am going to continue to dismantle the rest of it tonight.

I have new WMS Plat pistons to put it as well as crank bearings, seals, connecting rods, etc. and a gasket kit.

If anyone can think of anything I should look out for please let me know.

Thanks
Spencer

[Technical Support]

Re: Rebuilding a 657 Rotax

Watch our video on engine assembly tips.

[scarface]

Re: Rebuilding a 657 Rotax

Is this video accessable on this site?

[Technical Support]

Re: Rebuilding a 657 Rotax

Yes, from the front of the forums...SBT Videos.

[scarface]

Re: Rebuilding a 657 Rotax

Excellent - very basic yet good tips

[rpastir]

Re: Rebuilding a 657 Rotax

Spencer, I made a recent post about the same pwc. you must be more mechanicaly inclined then I am, Im thinking seriousely about a rebuild from SBT, I looked at my local crank refurbusher and just the crack is 325.00 if I look at the cost of all gaskets and then the process of balanceing or trueing the crank which I no nothing about, I think its better for me to take the long block with a 1 year warrenty then to do this myself. If you are going to do this yourself I would like to talk to you about your expertise and do this myself also. We would save what about 200.00 with out a warrenty. I just dont know if its worth the learning curve. what do you think?/

[scarface]

Re: Rebuilding a 657 Rotax

rpastir, I'm actually taking the crank itself to a shop today to get it tuned. I have everything else tore down and I'm cleaning it all up and replacing anything that needs to be.

I will be saving around $1000 by doing this myself as here the Seadoo dealerships are few and far between and they are all backed up until the end of the summer

[rpastir]

Re: Rebuilding a 657 Rotax

Hey bud, So you will save 1,000 by doing this yourself right? OK a long block from SBT cost around 750.00 Delivered with your core right?
Crank rebuild 350.00
Gaskets 100.00
Jug hone 80.00
Pistons, Rings 160.00
Head resurface 40.00
Where is the saveings vs a remanufactured from SBT with a one year warrenty?:emoticoni

[scarface]

Re: Rebuilding a 657 Rotax

I meant I will be saving over 1K from what my local dealership wants here to do the complete job - remove from hull, rebuild, reinstall - my local dealer wants over $2700 for the job.

I most likely wouldn't save over 1K by going with a rebuilt from SBT but I didn't do all the math to see what I would save - I started this project before I knew of SBT (as mentioned I'm new to PWC's) and had everything shipped directly to me.
And remember I'm in Canada, our money isn't worth as much and I have to pay a fortune to get heavy things shipped here and then customs on top of that... had I known of SBT prior to starting this project I would have weighed the cost of just buying a rebuilt from them with a warranty or doing it myself with no warranty and extra headache. I don't know if only $200 is worth all the trouble...

[Bill O'Neal2]

Re: Rebuilding a 657 Rotax

I get $1450 for an SBT motor installed, including tax and shipping to and from SBT. Your dealer is on drugs.

[Angelse68cal]

Re: Rebuilding a 657 Rotax

LOL Nicely said Bill! LOL

[scarface]

Re: Rebuilding a 657 Rotax

I get $1450 for an SBT motor installed, including tax and shipping to and from SBT. Your dealer is on drugs.

I completely agree... my dealer is a rip-off artist.
Now I need a rotary valve and a sproket - they want $53 for the valve and $80 for the sproket...

[Bill O'Neal2]

Re: Rebuilding a 657 Rotax

What is a sproket? Do you mean the brass gear? Rarely can you get away with just changing a brass gear, as the RV shaft gets bent when the brass gear shears off. Try SBT for a new rotary valve shaft assembly. Click on shopping cart.

New RV's are about $48.00 I think at the SD dealership. Buy online.

[scarface]

Re: Rebuilding a 657 Rotax

Yes, the brass gear, it's missing a little chuck from when 'something' went through the motor. I haven't checked the shaft yet to see if it's in tolerance but I may have to replace the whole thing anyways because of my 'clumbsy' hands.:(

I have a question: Something (the same something as mentioned above) went around in my rotary valve and took a piece out of my valve, I have a new one on order from my local (horrible) dealer but I am wondering about where the valve 'seats' - the 'something' made a few scratches in the case when it got caught behind the valve at high RPM (so it appears) and made a few scratches, they're superficial for the most part but are a bit concerning to me as I don't want to go through the complete rebuild only to find out that this causes issues, and as I mentioned earlier I have no experience with this motor.

[Bill O'Neal2]

Re: Rebuilding a 657 Rotax

That "something" is usually a broken bearing or bearing cage from the crankshaft or wrist pin bearings.

Even if you fix the RV shaft, chances are the motor is toast.

Unless you know exactly what went through there that you dropped down the carb yourself, you will probably need a new shortblock.

Small scratches in the RV surface will not adversly effect the motor. Big ones will.