I assume the plug has a single allen bolt in it? Go on..........take the plug out and have a look down the hole to see if the edge of the worm drive is visible......
Fwiw....seems 600/750 has no tach fitted, 900 does : pics show speedo drive plus DIN type connector, therefore electro tach. Need to find where the signal is taken off.....
It's a single bolt holding the cover on but there is nothing inside. It has (later) ST2 cams in it anyway. But (I'm fairly sure) there was nothing on the old camshaft either, although I don't have it any more to check...
