Well Stevie you may be surprized to know that your's is the winning guess being the closest to what I measured Off Camera I managed 2300rpm and a little less while the video was running.
So here are a few shots of the finished engine
Quite pleased with how it turned out and an enjoyable little one to make and would certainly suit those with smaller machines. It would be possible to do it without silver soldering the base for those that don't feel upto it by using a bit of JBWeld together with the screws to keep things held together.
A few video clips now, there is a bit of vibration as the speed starts to increase but it works through that and smooths off at the top end, I could not see any signs of balancing in the photos I based it on so did not include any but the flywheel could be played with id desired.