Bike Rebuild

[Albertross]

Sice you seem to be into the guts of your own machine I'll ask you. One thing I found out about my Busa once I had gotten used to it and started opening it up a bit, the bugger slips in and out of 3rd gear under fairly hard acceleration!!! Only 9000 genuine kms on the clock, any ideas as to what would have caused this to happen to such a young in mileage bike and also what appears to be a very well looked after example?? And that was 3rd gear NOT 2nd which you would expect!! One thing about this bike the gear change has always been a bit notchy too, quite hard to get used to..... I guess it's time to undercut the gearbox, any other suggestions??
Al