Brian,
I have actually done 550 miles on this set of pistons; am going to get to 1,000 miles before putting the machine on the dyno.
Engine has done more than 1,000 miles since total re-build, but had a light seizure twice!
First at 300 miles when I took it over 50 mph. Locked- up rear wheel on a rigid is interesting; suddenly you are in the on-coming traffic lane with black skid marks on the road, and brown skid marks in your pants!
Bike (and rectum) almost immediately freed up, and headed off home at a slower rate. Light seizure on LH pot; engine reconditioner who had bored the barrel, measured LH bore as 0.0025" clearance, so honed it to clean up, and 0.003".
Back on the road; 350 miles later same event!
The LH pot again: This necessitated a new set of pistons. The bore was recovered with a light hone. However I insisted it have the same clearance as the RH side (0.0035"). Obviously the clearance needed to be at least 0.0035"
Timing is 30 BTDC LH, and 31 BTDC RH. Carburation is good (definately not lean).
So far (550 miles) no probs, but I won't be exceeding 50 mph until I get to the 800 mile mark!
10 road worthy bikes in the shed; this is the only one I have had seizure problems with.
Cam is 334.
Pistons are 7.25:1 see below)
Happy trails!
Richard