Hey guys, I hope you are all alright.

I recently got an cbr600f2, and I took it to my mechanic for a revision and in his good intentions he cleaned the breather circled in green in the picture (that's not my actual tank, but its the same model), the breather part number is 17532-MV9-010 according to megazip. After cleaning it, the tank started leaking fuel from there, he said there were lots of dirt/rust inside of the tube.

The leak is heavy and doesn't make a difference if the bike is on or off. Leaked around 2 liters in less than 5 minutes.

Did we make a leak by removing the rust? Can the tube rust that much?
Bike has 30k km, almost mint condition and is from 1994 so it barely ran.

Until we find a permanent solution we've put a rubber tube coming out of the respirator and strangled it to stop the leaking, bike runs fine for now, do i risk making a vacuum inside the tank on a longer ride?

How difficult is it to change this tube properly?

I'm sure that the gas is leaking from there because i had to close the hole with my finger after I put gas for the first time after the revision.

Thanks for any insights beforehand.

 

I think that is the breather pipe that should connect to under the filler cap. It could well have rusted through and as a result allow the fuel to escape through it.
I suggest getting a cheap boroscope for your phone and have a look in the tank to see.

 

Run a tube from that opening up your console so it's higher than the gas level - that will stop any vacuum forming. Cap it with an aquarium on-way valve if you want to prevent any vapor escaping.