If you are not too sure or don't feel too confident doing this, maybe consider taking it to a garage for them to do. But yes, remove all the spark plugs. I would 'feel' the top of one of the end pistons through the spark plug hole by resting something like a screwdriver on the top of the piston to determine where in the barrel the piston is sitting ....
🤣🤣 I’m just reading this post for the first time and this reminds me ....
Back in 1975, I was the proud owner of a CB125S with a massive fairing, bought at auction for, I think, less than £100; my first bike. One fine day I was trying to set the timing or check tappets or something; totally inexperienced and ignorant with only, maybe, but I can’t remember, a Haynes manual for guidance.
Anyway I was trying to determine TDC, so I thought to put a pencil into the spark plug hole and see when the piston got tot the top. I turned the engine over using the kick start, the piston came up and ..... yep, snapped the pencil in two. Thus began my career as an amateur motorcycle mechanic.
What surprised and delighted me most was that the bike actually started when I put it all back together again. I don’t think I had such a joyful moment until 40-odd years later when my rebuilt 750 K2 fired up on the first push of the start button.
