Ive just fixed my friends bike (wr400f) that was doing a simular thing, fine all the way upto to 4th, click it Into 5th (only a 5 speed box) and he could cruise along. As soon as he opened it up slightly it "slipped" in a similar way a clutch slips but make a grinding noise. The selector had bent and the dogs had rounded off creating a ramp effect. So when he powered on it jumped into a false neutral. When he rolled off it slotted back in. It got to a point where 5th would engage but there was no drive. New 3rd and 5th gear and a selector fork and shes as good as new again. (Remember the wasnt a vfr, but gearboxes are similar in basic principles)

that is spot on what it is doing but it still means splitting the engine thou oh joy luckily I have got about six months to do it so not in a major rush could you tell or see the gear selector bent easily enough or not and I know its not the same bike but how much did the selector and dogs cost cheers

Sometimes you cant tell if there bent by eye, but if they bend the gear tends to wear into it so you can see where the gear has been rubbing. Its hard to explain over text to be honest pictures speak a thousand words. As for the dogs the edges of the teeth where rounded and not nice and sharp.

new genuine parts was going to cost him about £250-£300, I managed to find a complete second hand box that is mint for £100. Abd I did ghe work for him