How to make a DIY piston stop tool from an old spark plug 

This tool can also be used to create/check TDC marks on any engine. Just rotate engine against the stopper from both directions, clockwise and counter-C.W. TDC is in the middle of these points. In 4-stroke it would be a good idea to do it in compresion/power stroke to avoid valve damage. Nice handcrafting, I will follow Your guideline to make me a 'timing check' tool. Thank You!

Well. Made that look easy.

Very good idea.

How much of that bolt should go inside the spark plug hole?

Thank you sir.

Thanks for the video

Holding the flywheel to remove by pinning the piston is a risky bet... great tool though!