Thanks for the info, I did not realise the role of the secondary (2 arm) clutch. I thought it was only needed to allow you to peddle up to a reasonable speed before turning the engine over, and the outer (3 plate) clutch engaged depending on engine speed. I
I can not seem to let the engine slow to a low enough tickover that the clutch lets go on its own accord though.
I have found that if I run the bike on the stand and apply the rear brake, I can sometimes keep the engine alive by reving the throtte at the same time (as sugested by Futaba).