Did a regular 5,000 km oil change on my ‘10 sporty yesterday, I do the air cleaner at the same time, and found this. There wasn’t much oil residue in the throttle body, but just this slimey shit on the butterfly.

You can buy a myriad of different set ups for Sporty's, bolt on fittings, complete air cleaner assembly's even or just make your own using what you already have and off the shelf fittings, set it up like any of the others you have seen on here, I like to go down from the breather bolts, some go up and are convinced they can defy gravity but if you live in a climate that produces condensation....well.

My advice would be to leave it for another 14 years and see what it looks like then.

What's your usual trip length on the Sporty, Neale? Is it getting up to full engine and oil warmth regularly?

40 kms minimum each way on an outing on the sportster.

Mate just hit it with some carby/intake/throttle body cleaner and check it again in 3 months, it doesnt look terribly bad, some intakes get creamy slop all over them.... 

Well if its on the outside then logically its from the air filter.  maybe too much oil on the filter and it got sucked in with some dirt.  remember the filter will not stop all dust, only that above a certain size.  i have the same ish on my sporty.