Griso 1200 fuel breather ?

Anyone with a 1200 Griso experience this.
The fuel tank seems to be under a lot of negative pressure, so much so that sometimes the cap on the tank doesn’t want to open and I have to lift it quite firmly, and when it does there is a big suction noise, it seems worse when the fuel level is low and it all points to a blocked breather.
I spoke to a mechanic who said that these bikes do operate like that due to the fuel injection but its not something I’ve experienced before and I’m just not sure it’s right, any experiences ?

Are you getting suction with the engine running or stopped? If the latter then that sounds like a blocked breather, see other threads re the convoluted breather and drain and how to clear them.
Cheers, Gerry.

I think your right Gerry, i’ll have the tank off tomorrow but even that doesnt sound particularly easy.

I have a Griso 1200 and I’ve never experienced that. Filler opens just fine, and no negative pressure. Must be a blocked or trapped (kinked?) breather pipe.

Problem found, both the drain and breather outlets on the fittings screwed into the tank were blocked, a thick light coloured greasy residue ??
Some thin wire did the trick, off to Arnhem at the weekend a happy man !