2008 smr450 engine failure

Hey guys. My 08 smr450 crapped out at the end of last summer. Haven't touch it yet but since the warm weather is coming I want to get this thing rocking and rolling again. The bike stalled out while going about 15 mph and only thing I know is I pulled out the spark plug and the end was crushed. What does that usually mean? I'm no mechanic. And if the engine is too gone to rebuild where can I get a 08 smr 450 motor on the United states east coast that's not crazy expensive lol any help is much appreciated!

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First put it on a stand, leave the plug out, put it in gear and see if it will crank over by hand (slowly) by turning the rear wheel. Listen for any unusual mechanical noise or resistance.
That will give you an indication if the engine has major issues.
I would then take the head off and inspect the valves and piston.
I would think unless the whole shebang is stuffed then a minor rebuild would be cheaper than a replacement engine.

drain the oil and see how much metal comes out. You can also take off the exhaust and intake and have a peek inside to see if you see metal bits hanging about. agree with above, first see if the engine will turn over (slowly!). Never know what truly happened until you start opening it up. If there's significant damage the cost of repairs (especially if you aren't doing it yourself) can easily exceed the cost of a used engine (assuming you can find one).

Last I checked Halls had a very low mileage TE450 motor for sale, but it doesn't have a counter balancer and won't be as smooth as your SMR engine.

hmmmm.... I suppose if you're real lucky, maybe *something* went through the intake system and bent the sparkplug electrode on its way out, closing the gap & stalling the engine- without doing any damage (I don't know how a gap could close by itself, but maybe?). (cost: re-gap the plug; or if it was, for example, a ring fragment it could be slightly expensive to very expensive... new cyl, piston, head)

If you're semi-lucky, something like a bent valve, or fragment from the piston crown where the valve hit it, closed the sparkplug gap... but your engine was dying already because of a stuck valve or timing chain jump, for example. (cost: top-end job, possibly new cylinder)

If you have normal luck, you might've lost a bearing (eg. wrist pin, big end, or crank) and the piston crown itself closed the plug gap on impact. (cost: damage here varying from top-end job to very bad to total junk). This would've been kinda noisy though, so maybe there's hope.

Seems to me that kicking it over by hand w/o the sparkplug would tell you a little (compression could indicate a good situation or even a very bad situation; no compression might mean you can expect at least a top-end job to fix.

Dan- these are just off-the-cuffs guesses. We'll keep our fingers crossed! And let us know what you find.

Hey guys thanks for the help! I found metal in the exhaust. I took the valve cover off but can't seem to find a way to get the cam chain off

You have to remove the water pump, which pulls out through the top sprocket, allowing it to drop so as the chain can be unhooked. Undo the pump bolts and pull!

3 of the 4 valves were toast. Bottom end and rod are fine. Just need a piston and a head. I think I got lucky enough lol