Big end shell sizes

[SeanW]

is there an easy way to tell if big end shells are standard or oversize?

I'm going to bolt most of my R80/7 motor to a 100RS bottom end and thought I might as well replace the RS big ends while its all in bits

or do I just buy/borrow a micrometer and compare the crank journal diameter to whatever the standard size is supposed to be?

 

[SeanW]

...though I suppose to be pedantic, I really mean "undersize"

 

[cookie]

was reading the other day how you shouldn't regrind airhead cranks. hardening too thin or summat.

undersize shells exist for some undersize cranks from the factory. sounds a bit like bollocks, but who knows? anyway, your crank's probably standard