It was leaking mainly from around my nuts. It's cured now, it's gets a bit grubby around the filler cap but the seal looks like it's seen better days. I know what you mean about overtightening it, the long faces can bow outwards. I did that when i very first had the rocker cover off.
The threads for the carb top were shot, i decided to drill and re-tap them to M-8. I wish the material i use at work was so easy to chew through!


Couldn't find any nice shiny coated capscrews in this size at work.
Note to self - Drilling the job is usually better then drilling your own fingers.

Note to self No2 - Degreaser and open cuts hurts like hell!