You have it on the wrong scale or that is how it displays 330 ohms.
(multiply the values by the scale your using which is 1000 and you get 330 ohms)
either way it's right and your test succeed in telling you that the magneto is working as expected.
EDIT: Might as well add the expected values.
Ohm the magneto from the black and blue wire, 320-380 ohms is ideal, an open or dead short means a bad magneto if the wires are connected.
Ohm the CDI in the 10K-20K scale.
Red+ meter probe to CDI black wire.
Black- meter probe to the spark plug cap.
You should get about 6.9K ohms.
EDIT2:
This is a handy link, It's old but still relevant, Note that the multi meter on this page is reading 0.336 for the TZ magneto and .310 for the fat boy