After assembling con rods and crankcase assembly, I turned my attention to the timing gears. First off, getting the cam shaft gear on wasn't the easiest job I've come across - it was piggin tight and difficult to hold away from the bushes during assembly. Once on, having fitted the idler gear I checked that the two gears meshed and ran smoothly. They don't, and no amount of inspection and careful dressing with a diamond needle file sorted it. I spent a lot of time on this, and for the first time with this engine, was more than a little jarred off! Having said that, I could have caused the problem myself when I put the cam gear on, despite the fact that I was very careful. I'm aware that the idler is supported by the timing side case, but it's a good fit in the bush so for test purposes it should run ok just being located in that. Aside from the meshing problem both gears show signs of age and according to the Draganfly site, they have them in stock, but don't have the crankshaft, one, so as mine looks ok, I'll have to make do with what I've got and buy just the two.
Re the cam shaft, I'm surprised it has such a lot of end clearance. Am I correct in assuming it finds it's own position once running and under the load from the valve springs?