I am trying to rebuild this engine, because the piston seized. I am getting the rebuild kit. I believe I am good at following instructions. So I am getting the service manual as well.
What are the things I should look for?
What are the things I should be careful?
How hard/ easy it is to do this?
Where I can go wrong?

Anyone who already did this kind of job, please let me know about your experience.
Thanks
Nicky

If you have a digicamera, use it, unless you have a photographic memory. Take pics or all linkages, gov's, etc. You be glad you did. plus, you won't have to ask any q's about what goes where.

Why did it sieze, no oil???

Yes. There was no oil. Is there anyway I can move the piston without opening the whole thing. I tried to put WD40 and Marvin Mystery Oil, but couldn't turn the flywheel.

just take the header off, easy