You can't accurately determine TDC with a moving rod like that, as there's a 'null' area either side of TDC, where there's effectively no movement of the rod. You need a fixed Stop, made from an old Spark Plug, that stops the Piston a few mm before TDC. Wind the Engine slowly until the Piston hits the stop, and mark the Rotor in that position. Wind the Engine round the other way until it stops again, mark that point. Mid-way between the two marks is the EXACT TDC point.

With the spark plug positioned vertically above the piston, as on this Leader engine, it is straightforward to use the tool. Unfortunately most sparkplugs are positioned at an angle to the piston, so it would be nice if the video described how to use it with this configuration.

i have a 140 stomp pit bike and if it ant timed up right would it course it to run bad like it ticks over fine but when you rev it it bogs and engine gets hot very quick like with in a min or two but when u put the t for time at the mark its ment to be at it hits the valve so iv had to put the timing in a spot that i think its in it starts fine but dont run fine and its on the exhust stroke any help please on how to solve this

Thank.

WOW!!!