Filler cap leaking

only thing i would be concerned about is if fuel can get out water can potentially get in also if the bike were to go over (eg dropped) and leak fuel that could get messy

Point taken

Where do I get a replacement seal?

[flymo]

I think the seal is integral, it cannot be replaced. Best way would be to get a replacement original fuel cap and swap the lock component over.

[muzikill]

Yeah the microfiche shows it as a complete set. the pushing it down before you lock it is normal, thats it 'sealing' as far as i am concerned. You could try calling a official suzuki garage or emailing them. I'm pretty sure someone in the garage will have seen this and know how to sort it.

You could try a cut to fit bit of self amalgimating tape round the rubber seal to make it a tighter fit?

mmm I think it will always leak when full as it needs to let in air to stop the tank imploding, mine slightly leak if its full and propped up for a while.