Dave, I totally agree with you! I am starting to change my theory after thinking about it some more. If it was jumping out of gear then it would just jump out and do nothing.
It is only happening when leaving the lights when there is maximum load up to get the bike going, once rolling and in higher gears it is working OK. It is a real "bang" out and in, without me needing to re-engage the gear!!
I am starting to suspect it might be a failed or failing compression spring (item 43) for the transmission drive cam (items 40 & 41). Once again I have never heard of a failure in these parts???
If it is, then it is much easier to fix as I just need to remove the final drive. But it can wait, as I don't need a distraction to delay getting the 896 finished.
Any other thoughts or theories appreciated.