external oil filter

I fitted mine to the bottom of the channel section under the mudguard, but I don't have an original rear mudguard. What was clear is that bolting a mounting bracket to it is easier before you refit the engine! There's not much room on the other side!

Its pretty much out of view and easy enough to spin off the filter.

Heres another option http://www.nortonownersclub.org/noc-chat/technical3-light-twins-forum/894668325?b_start=0#668412224

... am looking for a pic

ta da ...