Just in case anyone ever needs to overhaul a 400 gearbox, @Linkin. Since the 2nd gear pinion is pressed on, you can press it too far, right up against the 6th gear and bind it, nasty. The float value for the 6th pinion is 0.44mm. I took that measurement before disassembling. The manual has nothing except the usual rubbish - 'Inspect the gearbox - does it have gears? Yes? Oh very well then, continue assembly.' This is not the Yamaha parts book, it is my spreadsheet that I make to double as a parts book/manual.