Wow......
Now that's some pretty bad damage.........and some great pix!
The first thing I would do, is determine what caused the damage. No use to repair it till you know what caused it. Do you do premix? It looks like it may have been caused from an oil pump failure or the oil/gas mix bad. Or, using the wrong type oil. It's probably going to fit into one of those categorys...
As for the repairs.......you got a few ways to approach this. If the casing an pistons suffered no damage and all the measurements come out good, then you can order a new assembled crankshaft for about $275. If you need a complete top end kit (pistons) another $273. Plus, a couple extra bucks for all the other accessories (Loctite, oil and the like) to put it back together. Or, you can put the crankstaft back in the block. Remove the PTO flywheel and all the other parts, magneto, exhaust manifold, carbs...etc and just buy a new engine for $745 and be done with it. You can order the new motor first, when it arrives, you'll know which parts you have to keep for yourself, then ship the other one back (which, shipping back is included in the price. You also use the crate the new motor came in).
You can find the material needed to repair your Doo at
http://www.sbtontheweb.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=1994sxp. Let us know what you decide to do. And great shots of the bearings and crankshaft. Thanks for posting them.
I'd like to hear other comments on what they think caused this to happen. I think it is an oiling issue. Any other ideas...? BTW Kev, do you know wha the compression of the engine was running before this damage occured and where you running WOT when it happened?