02 RX DI Engine Rebuild

[statikuz]

Hey everyone. I posted about this problem quite awhile ago but I couldn't resurrect that thread so here we go again.

Original thread: RAVE valves - damaged valve and piston, water in oil?

I haven't ridden them much since then but decided to get to the bottom of this. I knew it was already in rough shape so I did a compression test. 60 psi mag and 110 psi PTO on a freshly charged battery.

I took the head off and this is what I discovered:

https://photos.app.goo.gl/kaRfaGSJdhApDyKA7

Obviously it needs work, so the next step I guess is to pull the cylinders which might be a chore since I don't really have the capability to get the whole engine out.

Any ideas what could have caused this in the first place? I don't want to spend money on parts and just destroy the next piston too. It has about 140 hours.

I also have a 2003 RX DI that is in pretty decent shape, it is 124/124 psi compression.

 

[mikidymac]

From the piston top it looks like it was running lean but the DI is a lean burn engine. The rave can't touch the piston and it isn't broken so my guess is the piston/ring broke first then contacted the RAVE valve.

On a DI ski with this kind of damage and 140 hours you really should replace the crank also as there is a very slim chance it will last with just a new top end.

If your compression gauge is accurate the 124psi is a little low for a DI so I would try a second gauge.

 

[Barrys1976]

From the piston top it looks like it was running lean but the DI is a lean burn engine. The rave can't touch the piston and it isn't broken so my guess is the piston/ring broke first then contacted the RAVE valve.

On a DI ski with this kind of damage and 140 hours you really should replace the crank also as there is a very slim chance it will last with just a new top end.

If your compression gauge is accurate the 124psi is a little low for a DI so I would try a second gauge.

With the marks you see on the RAVE valve edge, are those reusable as mine look similar on a engine i just rebuild from the bottom up but i havent put it in the ski yet?

 

[statikuz]

Added some more photos to the album but it might be easier to see them here. Trying to keep this on a budget and my resources (tools and a place to work) are kinda limited. I don't ride these all that often, maybe 1-2 times a year.

Cylinder head cleaned up a bit.

Cylinders off (that was a chore).

Lost a good chunk of this one and the ring.

Exhaust port on the failed piston cylinder.

The good one looks OK.

Some damage to these ports on the bad cylinder.

 

[Sportster-2001-951C-Stock]

Has it been rebuilt? How well was it running before this happened? The DI has special coated pistons, be sure someone doesn't try selling you something that won't work. That one piston looks chipped from detonation, maybe stale fuel?

What if you toss a new/refurb top end on and a bearing seizes and a rod breaks, is it worth taking the risk?

 

[statikuz]

As far as I know it hasn't been rebuilt, it all looked factory painted over the fasteners and gaskets. Definitely could be from stale fuel, I have only used them maybe once or twice a summer for the last few years, not enough to run through the tank.

What's the easiest way to drain all the fuel out?

I never really noticed performance problems per se, but this is just casual riding so who knows. I do remember it making a terrible rattling noise and now I know why!

I will probably try and get the engine out and at least apart, should be able to do that with a friend and some gumption. Then I can at least take a look for any bits that fell down there.

Thanks for your help.

 

[Sportster-2001-951C-Stock]

Siphon out as much as possible, add stabilizer then fill full. It's best for fuel pump to keep tank full but stale fuel is especially not good for 2-strokes or really any heavily loaded engine (high fuel consumption equals high load).

Good luck with it, engine installation requires the seadoo engine alignment fixture tool to properly align crankshaft with jet pump.

 

[mikidymac]

Good luck doing just the top end. The crank isn't far behind.

 

[statikuz]

Good luck doing just the top end. The crank isn't far behind.

Why do you say that? What should I do/look for once I get the engine out and opened up?

 

[mikidymac]

You have a cylinder that passed debris through it and there is a really good chance it got into the crank bearings. That on top of the fact the 951 cranks only last about 200 hours and don't survive the added stress of a new top end.

 

[statikuz]

What should I do/look for once I get the engine out and opened up? Seems to rotate smoothly now but who knows what bits are laying in the oil.

 

[statikuz]

Alright, this was a chore but:

If I cut the steel clamps on the small black air line and clear water line from the air compressor can I replace with hose clamps or zipties?

Anything else to keep in mind?

Also drained all ~16 gal of gas out and it looked pretty nasty.

 

[statikuz]

Any ideas on a root cause for this?

Here is a photo from ~4 years ago when I first noticed this. Not so bad then.

Now that I've gotten it all taken apart. This is with an additional ~15 hours or so since that previous photo. Yeah I should have taken it apart then but I didn't have anywhere to do it.

There's about 1" or so of the upper ring missing. No damage really that I can see to the lower ring, it was removed intact.

I was under the impression that the RAVE valves couldn't intrude into the cylinders themselves (as this is a stock engine, not an oversized piston/untrimmed valve situation). Could the piston have failed first and then gotten wedged in the exhaust port and helped rip off the piston ring (and then gone out the exhaust)?

I know I was burning pretty garbage fuel so that's my biggest idea right now.

 

[mikidymac]

Yes. Even without RAVES you can loose a ring on the exhaust port like that.

 

[statikuz]

I've about got this thing apart except for getting the ring gear/flywheel off the crank. Got sidetracked pulling the fuel pump out and figuring out the filters.

I got the SBT puller, and read about not taking the mag cup off unnecessarily because I don't want to have to get new bolts for it. I got the big nut and washer off and threaded the puller on.

I have cranked on the puller as much as I absolutely can, have tried heating the gear up with a heat gun for several minutes, and banging on the end with a hammer and nothing. Any other ideas? Just keep banging away at it?

 

[mikidymac]

Have you tried an air impact wrench? The quick force typically pops them right off.

 

[statikuz]

I'm poorly equipped and don't have one or a compressor capable of it! I might see if there's a decent corded/cordless one I can buy.

 

[jhjesse]

Make sure you get 2002 engine parts. The 2002 DI is slightly different than previous years.

 

[statikuz]

Alright pending receipt of my impact from Amazon, anything else I should get on the way while I'm waiting for it? (seriously nobody in my tiny town sells one)

I have the engine out, and stripped down except the magneto flywheel and the top end is away at Full Bore for work (who knows how long that will be). I replaced the fuel filters while I was at it, that was cheap and pretty easy. Drained all the old fuel from the tank. The grommet at the bottom of the oil tank doesn't appear to be leaking.

Should I send the injectors for testing/cleaning? (it has about 150 hours)

Should I get new crankshaft seals for when I disassemble it to clean it out? The crank sounds and feels smooth but I can see a little bit of grit down in there so I figured I might as well get it all cleaned out.

I know I will need the engine alignment tool when I am ready to put the engine back in but that's a ways away.

 

[jhjesse]

Have to disassemble crank using a press to change seals. Not worth it.
New crank comes with seals. Get a counter balance shaft while you are in there.
You can get an OEM reman crank from your dealer with exchange. Probably best deal.
Yes you will need an alignment tool.

 

[statikuz]

According to the dealer they don't do OEM reman cranks anymore and I wasn't really planning on spending another $700 on this project but I might change my mind once I get the bottom end open. I just meant the end seals not the internal ones.

 

[mikidymac]

Sounds like most dealers are full of crap and just say everything for the 2-strokes is not available.

Here is direct from Pro Caliber out of Washington with free shipping and shows it is still available.

421000571
REBUILD-CRANKSHAFT 947DI | Includes 1 - 5.
This part replaces 290887767.
MSRP: $492.99
Dealer Price: $419.04

 

[statikuz]

I called them, they said they don't have it available and said the part shows "backordered" from Seadoo, but they gave me another dealer that showed one "in stock" in their system so I'll try them tomorrow (closed today) just for the information.

 

[statikuz]

Alright, saga continues!

Received impact (that thing works great for $80).

Apart:

Crank and counter balance out. I could not find any bits of grit in any of the bearings and they all spun smoothly by hand so I opted not to replace it. I called around and nobody does rebuilt OEM cranks anymore and I didn't feel like buying a whole new one. I only put about 5-10 hours a year on them so that's a risk I'm willing to take.

Icky:

Cleaned! Scrubbed them in a Rubbermaid tub with hot water and Simple Green and they turned out real nice. All the bits that look like grit in the photos were just bits of sealant material, I didn't find any metal in there at all.

Bad!

Good!

Reassembled. Yes I know in the photo the counter balance shaft bearing lubrication hole is not up like it should be but I fixed that. All the pins where they should be, alignment marks on crank and shaft aligned, gear oil added to gear cavity, grease on lips of end seals.

Found at the only powersports place in town, they also had Yamabond but everywhere I read said this was the ticket. I struck out finding a foam roller (no crafts places here) but I used my finger and it worked OK.

Got it all put back together and torqued down per the manual. That Loctite threadlocker stick is amazing. I just put a bit of dielectric grease under the bolt heads in lieu of the Molykote 111 it calls for after reading a bunch of threads about that.

Question - in the instructions for reassembly of the air compressor it says to use a new screw. Can I just find a new M6 x 45 screw and use that or is the Seadoo one magical? Alternately, should I get the whole compressor rebuild kit?

Also should I bother with sending the injectors for testing/cleaning? I'd like to know what caused the failure in the first place if I can.

Still waiting on top end from Full Bore - they finally emailed me back to let me know they're closed until August 13...

 

[mikidymac]

Yes you have to send the injectors out to be sure they didn’t cause the failure.