I've got the tank off my NC31 for respraying. When taking it off I noticed that there are no pipes connected to the stubs underneath for the breather (smaller one?) and the overflow/rainwater drain (larger one?). There are no pipes hanging loose either, where they might have fallen off or not been connected after the tank was last re-fitted.

Can I assume that there should be pipes connected here? If so, where do they drain to and how long are they? I assume they'd just hang down through the frame to somewhere under the engine?

Thanks for any help on this.

You are correct there should be two rubber pipes fitted that are routed down between the aircleaner and battery box .
While the tank is off just make sure that small one is clear by blowing through it any restriction can cause running problems.
They need to be long enough to exit below the frame and exhaust

Cheers - many thanks!

Not sure if I helps, but mine hasn't got any rubber pipes either.
Must've been the rubber pipe monster....