What to look for regarding bad crank crankshaft crankcase, etc...

[dmixed]

I am about to tear into my SeaDoo 717 engine for the first time. Been years since I've done mechanical work. I have 90psi compression in one cylinder so now I'm weighing my options... prob gonna go with a full kit and considering replacing crank with a rebuilt, but...

My question is what to look for when I remove the top end? I know if there's "play" like side to side and seal leakage would be a concern, but wondering if anyone has specific testing or visual inspection hints on what really means you need to replace/rebuild crank? Wondering how these "typically" fail?

I'm not seeing a lot of consistency with crank failures and since I'm tearing apart engine figured I'd ask here for hints, tips, tricks, etc.
If anyone has photos, please post you're failed crankshaft issues.

I just don't want to reinstall everything (new top end) and discover a crank issue soon after so really thinking maybe pay what I'm seeing as $250~300 for rebuilt just to make sure?

Some discussions even say they are extremely reliable on this engine so also thinking I'll just run it til dead, but on the fence about this (cost is a chunk o money too)

 

[azsxr]

Look for metal and rust and then how do they spin? what do they sound like?

 

[etemplet]

I would not tear into the bottom end unless I found a problem but if you have the engine removed you can check the crank. I've flushed the bottom and and let it soak in oil for a few days. Another cleaning and flush and install the top end. Doing the crank adds a lot of money to the rebuild. I do condition based repairs. If you are doing all the work yourself getting the crank done isn't a bad idea. You'll have a new engine. Good Luck !!

 

[dmixed]

I realized I did not post before ... this is a 2000 GTS with what looks like a lot of hours and many original parts.

So far I've done the fuel system (yep, those nasty grey lines were there) and all electrical and shiny carb refurb.
WSM piston set on order.

Thanks for the advice everyone! The crank moves very smooth and no gritty noise or anything.
No excess oil like a seal problem or anything else I can see.
Seems very solid and to me looks really clean... anyone else have opinions?
I was told the bottom was rebuilt, but the top wasn't, but it had the cageless bearings (ugh!) so that makes me wonder if any work was really done?
Can't imagine someone putting back those cageless bearings, but I guess anythings possible.
I covered everything and counted 34 per each side so I'm fairly confident I can leave this bottom end alone for (hopefully) a few years.

 

[etemplet]

I flush the bottom end with diesel, work everything, roll the crank, rod bearings, dump it out and give a good listen. Push/Pull on the rod bearings then I flush again and blow out gently with compressed air and wipe what I can. It's gonna make noise because you don't have any oil in the bearings but you shouldn't feel any bumps and the rod bearings need to spin smoothly... no catches or roughness. Doesn't have to be perfect but nothing "glaring". A good bearing is a good bearing, age doesn't matter that much. Bearings are designed for 1000's of hours of use. So you're gonna doubt yourself and maybe wonder but don't spend the money without good sound reasons.

I'm with you... nobody is gonna do a bottom end and not do the top and all those "needle bearings" testify that the top end is original. We have trouble finding and accounting for all of them when we do a top end. LOL

Before you assemble the top end and install the cylinders slowy pour some oil into the small holes in the upper casing on each end. There is a little slot there with a hole in it. Make sure that hole is clear and you are getting oil into that area. That oil feeds the outer bearings on the crankshaft. I also pour a few onces into the bottom casing and work it around. I want good lube for start up.

Get some engine assembly lube for the cylinders, rings and such and DON'T pack the wrist pin bearings full of grease. I use just a little synthetic some people dont use anything at all. Sounds like you got a pretty good plan. Good Luck !!