Rothewald TDC FINDER Mode D'emploi page 12

First, place the motorcycle securely on the stand. Turn off the
ignition. If necessary, remove the tank to access the spark plug
shaft. Remove the spark plugs for the cylinder on which you wish to
determine the top dead centre (TDC) or the ignition timing. Slowly
move the piston upwards by turning the crankshaft.
D E C A B
Now prepare the TDC finder: Unscrew the locking screw (A) of the
TDC locator pin (B) so that the pin in the TDC finder can move freely.
Turn the scaled middle section (C) upwards so that its thread (D) is
almost completely inserted in the screw-in section (E). Set up the
scaling (C) in the zero position and make sure that it does not twist.
Then fit the TDC finder in the cylinder head. Slowly turn the
crankshaft with a tool back and forth around the upper dead centre
until you have determined the top dead centre (TDC) as precisely as
possible (pin (B) is in the highest possible position). Secure the pin
with the locking screw (A). Turn the piston back slightly towards the
bottom dead centre (BDC). Adhering to the workshop manual for the
vehicle, set the ignition timing in millimetres before the TDC on the
scaled middle section (C) of the TDC finder by screwing it in (turn
to the right). A scale mark on the dial (C) equates to 1/10 mm. If
the ignition timing is 1.7 mm before the TDC, for example, 17 scale
marks must be screwed in.
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