Old Bernina needle timing tips?
 

I've seen the youtube vids of needle / rotary needle bobbin timing for various machines, but none of the rotary needles look anything like my 117 and 540 rotary needles, so it's hard to relate them. Does anyone have any tips on how to time the Bernina 117 and 540?
What's the 'standard' way of doing this? (I can do it blindfold with a motorbike motor!)
Is it a matter of aligning the rotary with the needle when fully down? or when it's just entering the bobbin? Or what?

First make sure the feed dogs are working with the needle. Needle is almost level with the needle plate as the feed dogs drop into the needle plate hole. I believe the 540 has a back facing hook. The hook hits the top of the eye of the needle, on the needle's way up. Also, there should just be a thread's space between the hook and the needle -- almost touching -- needle/hook distance -- something like the gap in a spark plug.

Good tips Annette thanks. After plenty of trying I've finally got it to hook up. (It's difficult to see exactly when/where the needle co-incides with the rotary hook because other components block the view). And when you do get it right, the grubscrews that hold the rotary to its shaft are around the back - inaccessible! Anyway I got it in the end. It remains to be seen how well!
Fun? Yes, also the rotary contraption needs to be positioned correctly laterally along it's mounting shaft too, otherwise the needle scrapes against it. Quite fiddly, but I think I got there. The bobbin thread is picking up, and the machine is doing a passable stitch (even if it is turning by hand because I don't have a footpedal to power it).
Cheers Annette.

I don't do any major adjustments until I have had a few rounds of thorough cleaning and oiling. I have twice had a 201 with a needle scraping against the turning part under the hook and race. In both cases it turned out to be oil and grime behind the groove in the needle bar causing to push the needle off position. I have had similar things with sticky swing arms, and hard packed, felted up dust in connection with feed dogs and bobbin cases. Timing issuse happens now and then, but they are not the most common reason for problems with upper and and lower thread not interlocking as they should. I hope your new machines cleans up easily, foot controllers included.