Up and running again after several delays finding pistons and waiting for barrels to be sleeved and bored to standard.
Around £500 out of pocket for pistons, gaskets, parts and machining, all because someone forgot(?) to fit two ten-penny circlips in the gudgeon pin ends - one from each piston. Wrecking the engine only about 3000 miles after re-bore and re-build (2,500 in my ownership).
Unfortunately I use my 5TA much more often and now too much time has elapsed to even trace the culprit.
Just got to keep my fingers crossed that it settles down nicely in time for a Spanish trip in mid-May.
Incidently, I now have two +.040 5T Triumph Speed Twin pistons which are not damaged, virtually as new, but without rings if anyone is interested.
Jim.