Second gear dramas (another one!)

[drworm]

Hi guys
I have a problem with second gear 'slipping' out and back in when accelerating. I understand this is reasonably common.
Luckily I work in a decent machine shop as a toolmaker, so have access to milling machines etc.
I am curious about undercutting the gears, or just recutting them square again if they are not too far gone.
I realise to take the engine out special sockets are required so I will machine some up tommorow after a few measurements. Any SA guys will be welcome to borrow them.
If anyone would like to share their knowledge/experiences I would be very grateful.
So far I have established I should be replacing the shift fork, and inspecting/replacing/remachinnig the gears. Any other tips?
Thanks guys
Ben