How do you set the ignition timing when you have a non-g40 auxiliary pulley fitted with no 'z' ignition timing mark on it?
Spark plug out on cylinder #1, TDC feeler/pointer (or pikey alternative of screwdriver or 3/8" extension bar etc.) down the plug hole, rotate engine with ratchet on the crank bolt, and rock back and forth 'til you feel that the piston is right at the top of the bore.
Now you know the engine is at TDC, so you can make corresponding marks on the crank pulley and block/cambelt cover. You then use these as your TDC reference, and use a timing light with dial-in advance to set the ignition timing to 5° (+/-1°).
Whilst you're at it, set the idle speed with the blue temp sender unplugged too. Engine needs to be up to temp.