A pack of mascotte rolling papers gets my vote.
Fold the lid double, and its just about exactly 0.40 mm thick , and usefull as a feeler gauge for both the spark plug gap and points gap on old german and Japanese mopeds.
Want to know exactly when the points open, put a rolling paper in between the points, turn the crankshaft while pulling the paper, when it starts to slide out , points are opening.
That and and old sparkplug socket with an old 14mm socket welded on the 1/2 inch drive side, and an old flathead screwdriver shank welded on the side as a handle.
Shank had two grooves ingraved in it, that lined up with the top of the sparkplug hole in the cilinderhead.
1 was top dead center, 2nd was 2mm below top dead center, very useful for setting ignition timing when your points fail in the middle of no where...
14 mm is for loosening the Bing carburetor float bowl.
Flathead screwdriver for engine covers, airhose, carburetor mounting screw, and a whole load of other stuff.
That silly contraption saved me from walking home a lot of times...
Before I could get the engine shut down that socket took off like a chrome meteor and it took me 20 minutes to find it. Had it hit me in the head I would have been in the ER!
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