Grenaded GasGas 2 Stroke

What year, CC, hours and fuel type? Just curious. Sorry to see! 

Sorry man. Tell us more as asked above. There has been a couple Katos with pix like floating around the last few years. 

Need more info, but that’s an expensive fix for sure

There was a recall for a different CDI in 2023 bike last I believe.

Piston intake skirt may have hit crank? Was new piston OEM Vertex?

I've never seen a 2 stroke do anything, even remotely close to looking like that.  My expert opinion is that you had a mud dauber nest in the exhaust and you tried drift starting it by jumping it off your house.   How else could that happen? That is crazy. 

If there is any intake skirt left measure the thickness of it versus the original piston. Vertex had a quality control issue with some pistons. It was talked about in the 300SX thread. The inside of the skirt can hit the crank. Maybe the 250 as well?

This is a carb bike, not a TBI bike.   There is no known issue with piston to crank contact on the carb bikes.  Also when the piston does contact the crank it does not usually present in this manner (head blown off).    My initial guess is this is more likely a rod failure.

What does the top of the piston and bottom of the head look like?

Omg, that sucker blew! I’ve never seen a failure like that on a 2-stroke. Shoot

I know it sucks and all.....but part of me thinks that looks pretty sweet.    The blown piece will always look cool on a workbench.  I've got bent valves from a small block 350 build as trophies.

Could be tied to manufacturing defect....  I heard from my dealer (Triumph) that a lot of the manufacturers have been having quality issues since the Great Flu shutdown.

If something got between the top of the piston and bottom of the head, there would be visible damage to both, with it still assembled.

Gonna assume you are ok?  Let the bike go to hell....it's fixable.  Hoping you are alright.

From the cracks around the head, it looks like the top of the piston collided with the bottom of the head around the squish band, it's likely the bottom end or con rod failed.

Yup, that is a crank or rod letting go. 

The good/bad news is that there’s a couple guys parting out brand new bikes and even at the proud price they are asking, it’ll be cheaper and way less of a headache to rebuild yours. 

Also perfect opportunity to drop a 300 kit on it since you need all those parts anyway.

How many base gaskets are you running to get the proper squish clearance when you replaced the top end? Clearance Looks pretty tight

If the wrist pin bearing and stuff was in the exhaust, it might’ve been the circlip that came off, but the piston and head should’ve been scratched up. The head shouldn’t have broke under any circumstance. I’ve locked up soooo many two strokes and have never seen a head do that. When you rebuild, I would suggest an aftermarket head like vhm.

These are brand new bikes, taken apart and sold as parts, I’ll try and find a link to his eBay page, but he posts on here as well. 
 

Mav ~ help me out here… he’s posted on the for sale section several times. 

That’s insane. I’m assuming from the fact that you are posting that you are relatively uninjured? Glad you’re ok.