What model compatibility should I look out for when shopping for a fuel filler cap?
Something like this: http://www.motomummy.com/store/product. ... 82&page=1

e.g. Levers are compatible with CBR600F's, etc...

If it's for the nc30 the honda version of the harris cap should fit any honda model. If it's for the nc35 take note that the harris version pictured does not have a vent tube or hole so would be unsuitable as the nc35 vents through the cap.

Thanks, I got a VTR1000 one, fits my NC30 fine.
Interesting though, that only 3 bolts actually hold it down, and the other 4 (on the original cap) do nothing at all but look pretty...