Because you can't see the piston, how do you actually know its at t.d.c.? The straw is placed down the spark plug hole to feel the top of the piston. You turn/rock the crank very slowly right and left, as the piston should be a t.d.c if the chain is good, but if its not the marks might be lined up and the piston is not actually at the top. You will see/feel the straw move up and down when turning the crank. Feel for t.d.c., when the straw is as high as it gets, then look at the marks to see if they are on, or not lined up when you 'know' the piston is at the top.Im so confused now lol okay so i turned the crank over twice til it hit tdc and the t and lines are lined up on the crank. The picture above of my chain is what it looks like when at tdc. I adjusted the valves at tdc as the manual said. So im confused on what you are saying i should try next? What does the straw do and where do you put it and what do you get from doing that?
Oh, remove the straw before installing the plug, a long straw works best