Oops, sorry, I misread (because of the way the one hour was on one line and the 40 minutes on the next). I thought it was 40 minutes.

1:40 is doable if all goes according to plan - but it's probably still not something I would risk on separate tickets as there is still relatively little leeway.

I once read, somewhere here on FT, that some travel insurance policies stipulate a minimum of four hours when connecting on separate tickets, and four hours is the figure I have adopted as my own minimum. I did break that rule once when I booked a two-hour connection at AMS (KM to KL), but I did this in the full knowledge that I was taking a risk and that I would be on my own if I didn't make it, and I did have contingency plans.