Yamaha haven't been uncooperative, as such, they've just given up without fixing anything, saying they couldn't find anything wrong, and are basically saying take it to the dealer, who I've already said are ignoring any requests for warranty inspections.
To be honest I've spent so much time and agro trying to sort this, I have given up. I just use it to go to work and back, and when I've got some money I'll trade it in for something else. It won't be a Yamaha, of course.
And30ers - my clutch judders and slips when the bike is cold. I've taken it back twice. The first time they did a service, and seemed surprised when I asked if they'd checked the clutch. The mechanic then gave me some bullshit about how it was common in Yamaha cross plane technology bikes, and an oil change was the cure, which it wasn't. I took it back again, it went to Yamaha for 6 weeks, and came back still stalling and as far as I know the dealer didn't even mention the clutch problem to them.
I've sent the dealer 4 emails asking them to look at the clutch again, they haven't replied to any of them.
The result is that I have to be careful not to let the revs drop when I pull away, to avoid stalling, but I have to pull away gently, or the clutch will slip.
Forgive me for ranting, but I have a seriously defective bike, and the warranty hasn't been worth the paper it's written on.