Very hard to find now and no longer available from Yamaha, this pink hose is very similar to the type that the bikes had when new. Don't ruin that restoration when you can now get the hose you need.  Listed as 4mm X 6mm it is a nice fit on the both the overflow and vent stubs on Mikuni carbs.  Supplied in pre-cut lenghts of 1 metre.  Suits:

RD350 YPVS LC2 1983-1985 (31K)