Iron Head wrote: am unsure about the theory that crank end float can somehow be taken up by tightening the drive sprocket nut and thereby somehow sliding the crank through the inner races or by the outer races moving in the drive side crankcase housing.
I think the end float requirement is only relevant during assembly and is just a check to ensure that there
is end float, thus avoiding pre-load on the t/s bush.
What I am not understanding from reading the old manuals etc is how the tight to crank and crankcase main bearing system permits any end float/movement of the crank left or right.
As with your method I've also always fitted the mains in the the heated c/case and then installed the flywheel and shaft assembly. The correct end float has been there without any need for further attention although I've not found that the axle has been immovably tight (or loose) in the bearings and generally the whole assembly goes together with a satisfying 'clack' from the axle as it hits home on the inner race.
I may be having a geriatric moment but ISTR that somewhere in the depths of the manuals there's reference to the inner main bearing being a looser fit in the c/case than the outer one to facilitate moving it to obtain the required end float. On the other hand it's suggested in manuals to achieve the end float by machining the face of the t/s bush.
Anyway, just as long as there is some end float before the rest is fitted (s/absorber etc) it'll be fine. My only thought is that if there was too much end float the scroll on the t/s axle might not mesh 'nicely' with the oil pump plunger although if the drive axle and bearings are to spec'n and correctly installed that wouldn't happen.