If the 650 is like the 1000 there is 2 pipes.
One is a drain for any fuel that is spilt when filling.
The other seals against the fuel cap, on the 1000 it has a red rubber grommet that meets the cap when closed, that is the vent.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.