Kid,
Your configuration is exactly how Norton delivered the early 961's.
The drain hose from the airbox is routed down to the lower frame member along with the tank vent hoses.
It drops oil if the drain plug is removed and there is oil in the airbox.
Otherwise, with the plug in place, the airbox can fill with oil to the point where is may foul the intake.
I had the factory Oil-in-Airbox fix kit fitted to my 961 last year.
the kit includes several parts designed to help the engine breather do it's job without spitting out volumes of oil into the airbox.
The small catch bottle that comes in the kit is fitted behind the left side footpeg plate and is undetectable.
My kit works perfectly.
I have put on about 600 miles since the installation, and the bottle is still dry, oil level in the tank is now constant.
The reasons for my purchasing the kit:
1. My oil level would have to be topped up every 3 or 4 outings.
2. Small areas under the bike in the garage were greasy due to dropping from the airbox drain hose. Like you are experiencing.
3. The main reason: noticing that upon startup after sitting for a few weeks, the airbox drain hose would push a fair amount of oil out.
I didn't notice this until much later and that was the final straw.
