Originally Posted by
Kairos
No it doesn't need to be. You do one side first, I tend to do the left hand cylinder first because then the right hand one is not so far to turn over afterwards. Crouch or kneel beside the bike the side you are doing, because I don't have a bike bench! You then watch the valves open and close as you turn the wheel, 3rd gear works well for me. Once the vlaves have both closed you can turn the wheel/crank a bit and put the 'indicator', I have a length of oily dowel somewhere, but I couldn't find it so used the screwdriver as a stand in, into the plug hole touching the piston, watch the valves and the screwdriver moving outwards, then as the valve opens you can move the wheel in tiny increments watching the screwdriver, when it stops moving you are near enough at TDC, a head torch fine tunes TDC with the flywheel marks in the little hole. It doesn't have to be EXACT, so the fact my timing mark is not to the micron lined up makes no practical difference whatsoever. These are old, push rod engines, not highly strung modern ones. That is another practical benefit.