Yes. After installation I discovered my fastback tank would not fit. In my case, the tank is a Fiberglass Fastback replacement tank from Burton Bike Bits. Per them, it is, in every way identical to the OEM tank but since it is an aftermarket tank, I assumed there was some difference in the underside that affected the fit. I asked Madass about it after having the problem and he said that the kit would fit any Norton original tank but, of course (and I completely agree) he could not know about the fit with an aftermarket tank. I had some further discussion with Burton BB and they again stated that the tank was identical in all dimensions to the original Fiberglass Fastback tank. But who knows? Since I don't have an original fastback tank, I can't say. Like Joe, I also had to slightly enlarge the left side carb screw holes to align with the Amal Premiers. Perhaps the Premiers are slightly different spec-wise than the originals.
It was disappointing to have to un-install the kit.
I took it to our moto club meeting and everyone was impressed with the quality of the machining/bearings, etc. Several people said they wished they had Nortons just so they could buy/install it!