Wow Doug, the whole enchilada, very nice mate. I have just the pistons and rods from JS. And really please with the reduction in vibes. Makes an 850 more like a 750 for vibes. I have the Gapless rings too, you will find kicking her over requires a firm and full kick, no pussy footing or she will bite back.
Shimming the crank is not too hard. If you have the mains still on the crank and in the cases, reassemble the crank into the cases for a dummy set up. And check endfloat.
The manual does not clearly show the shim, but you can shim either on the crank or in the cases. The timing side bearing fits on the crank and in the cases are looser then drive side, so do your shimming on the TS. Old Brits is a valuable source for information and also he supplies a shim suitable for shimming the outer race in the case. Norton supply a smaller shim to go between the crank cheek and the inner race. Caution the inner races are pretty hard to get on and off the crank, you need a really good bearing spiltter. So it is easier and safer to do your shimming at the case.
check out Oldbrits site!
Oh when you fit your fancy new pistons, and aren't they sex? you need to get the ring gaps orientated correctly, I found it easier to fit the pistons complete with rings into the barrel first, then fit the barrel/piston assembly to the rods. Obviously fit the inner gudgeon pin circlips first. Get some spacers to hold the barrel of the cases, whilst you fit the gudgeons. Some short 3/8 unc bolts in the outer barrel stud holes works nicely.
Did you get a copper shim gasket to fit between the barrel and the crankcase? Jim has some dimensions for the piston crown to top deck height. You can fit he pistons without rings and check how low the pistons are in your barrels at TDC This will give you and ideal of the compression ratio you will end up with. I went for 9.25:1 and it runs very nicely. I used a shime to get the height I wanted. Jim has them.
Cheers richard