Thanks for the nice comments on the BSA. Meanwhile on the racer...
I had plumbed the 'spare' sidecover for an external oil cooler. It should fit, looked like it would fit, and it did fit except for one little ole thang. The clutch activation mechanism. The original uses a little pan-piston to engage the internal clutch. The 'spare' has a machined boot in the rod that looks as it would interface with a rod of some sort. Anyway the difference is enough for me to call the spare 'practice' and commit to plumbing the original. Anyway, it turned out better the second time around.
