Burn down question

[cubby]

So I bought a 2000 summit 700 HM for a summer project. The guy I bought it from said he got it on a trade deal and it had a top end rebuild done to it just before he got it. While he was breaking it in it locked up. He took the head off and decided he didn't want to mess with it so I bought it. I tore it down and this is what I found. What do you think caused this. Lack of oil, to hot, or not letting it warm up before hammering down?

 

[sno*jet]

a buddy had a 2000. when his stuck a piston the dealer said there was an update to the oiler that was never done. basically just turning up the oil injector i believe.

 

[cubby]

Pretty sad at how slow this site has gotten over the years. Hell I posted on dootalk and have lots of comments and advise as to what to do. Seems like if a guy doesn't have a 850 no one cares around here. Or it's just the same 10 people everywhere on here.

 

[summ8rmk]

I had a 2000 summit 700..
The only issue i had with the stock oiler setting is crank bearings. Locked up at 1,756miles. After rebuild, turned up oiler and my brother still has that sled with over 5k miles now. I know he rebuilt it again just after it hit 5k. Bearing again...

To me, it looks like it wasn't warm enough before riding...

[emoji507][emoji192]

 

[skidoome]

If the engine was using the correct amount of oil I think it could be:

Forged vs Cast piston clearance issue.

Forged pistons grow faster then the stock Cast pistons and are easy to cold seize.

If the bore wasn't sized to the forged piston this will happen unless extreme care is used.
Have seen this issue a lot with back yard mechanics.

 

[eddy]

700 Bore

If the motor go real hot with the previous owner the bore may be out of round. Clean the aluminum off the bore and check the fit of your new pistons. Check ring gap in several places as well. BTW we have used that exact piston in that motor and they work great. Set the oiler to spec (maybe the 2001 and after spec?), use premix until you can verify the oiler is set to deliver at 36/1 or so while in use.
BTW looking at the pictures: if the previous rebuild had a buggered base gasket union surface you may have found a problem. Also check the water pump impeller, or just replace, as when a meltdown happens: the impeller may have caused it or is damaged by it. Best stuff to use for cleaning the base gasket surface is a Loctite product called Chisel.

 

[cubby]

Thanks Eddy for your advise, I will check into all of that so I can ensure that it runs like a top long after I'm done