Seized Motor With Shattered Piston

Might be an idea to let us know what bike & engine it is, we can see its a twin and guessing its either the timing has slipped or one carb has run weak and burned a hole in a piston.

I personally would strip the lot down to make sure you get all the debris out otherwise it could be an expensive second rebuild, also check head & valves for damage.

 

The pistons should be the same distance up/down the barrel. Those two aren't! Therefore I would guess that something else is broken. If that is the case then removing the barrels may well take the seized piston with it, but leaving behind heaven knows what. From the photo it looks like the gudgeon pin is still attached to the piston (difficult to be sure) which begs the question where is the con-rod?
I don't think, from the look of it, that the holed piston will go back down the bore so if it does come away with the barrels it can be removed from underneath - with a BIG hammer!! Probably.
Can't help thinking that the crank cases will be full of small metal fragments which shouldn't really be there.
Sadly it looks like a load of work for somebody. I really, really hope it isn't as bad as it looks - a holed piston on its own is not necessarily the end of the world, as my Norton 88 once proved. But a holed piston stuck at the top of the bore with its mate halfway down does not bode too well.
Good luck with it.

 

A project for the winter.
Prepare for a full engine re-build and a few new parts.

 

The shiny bar visible through the hole in the piston crown is the gudgeon pin. You should not be able to see it

a) because the piston is intact!
b) because it should be sleeved by the con rod small end which is connected to the crankshaft at the (lower) big end.

As a minimum you have a seized piston (with scored barrel) and a broken conrod. You also have a heap of shrapnel in places it does not belong. You need to strip the entire motor. The barrels will lift off with the seized piston that should hammer out and you can then see if there is any bottom end damage. Part of the diagnosis needs to be causation - lean fuelling or a lubrication failure?

You need to judge your own competence but the more you do, the less the eventual cost. You will certainly need some machining/honing of the barrels and maybe oversize pistons plus whatever lurks below.

Good luck. Find a competent local shop!

 

My guess is that the sludge trap is the problem and the right hand rod has failed on your T120, please let us know how you get on with the strip down. Hopefully it has not done to much damage to the other parts.

 

Bloody hell, what a mess!