motor size?

[york,pa-katrider]

i bought i pre kat for parts motor runs good there is a different motor in it how can i tell what it is?

i have the title and my nephew wants to get it up and running this summer but i have no clue on this motor...

[Lagmo]

you could try posting the Engine code and cylinder CC?
The VIN model code might help too

Engine code will be in the format 'X7NN-Serial no.' and is usually stamped into the block on the righthand(throttle side) of the engine.
X= Either of the following letters: 'N','R' or 'V'
NN= A two digit number.