The manual states:
Bore size 72.97 - 73.02mm.
Wear limit 73.1, which I make to be 0.08 larger than the upper bore size limit, and which I calculate to be .0031"
So if it's gone oval and the diameter is outside the limit I would agree probably time for a bit of work. I think .50mm oversize will do fine.
I usually use Nametab Engineering in Redditch. Simon is happy to deal by post. Send him your barrel and new piston . Call first! He is old school and doesn't do much by text or email if he can help it!
Borderline, yes, but if you hone it to put a new set of rings in, that will take it over the line, so I think while it's apart, do the job properly. Much more satisfying
