Hi Keith. I can sympathise with your non starting. I have had a few episodes of this checking and rechecking things. I would do a compression test to establish it is getting something like 100+ psi in each pot and if this is OK, check the crankcase door and transfer port covers are sealing well (I have used grinding paste on the part where the cover fits) and then pour a decent amount of oil into the crankcases via the transfer port when they are off. Personally I have never really known my bike ever complain about too much oil as long as you are not stupid. It should now start and continue to run and unless there is something really wrong with it the other things tend to fine tune the running.
When you release the strap holding the crankcase doors on, and it has been running, the doors should not fall off as I discovered mine used to. This highlighted the fact that they were still leaking slightly. The doors will blow off under compression when you kick it over and this is how you want them to fit.
Everyone’s experiences seem to differ though!