Ha presumably taking the chain off first !!I'd fit it, fire up the engine, stick it in gear and give it a tickle with a flap disk on a grinder, flip it over and do the other side.
Totally agree Pete as said on the honda 500 crossers they use 520 and my kx 500 two stroke and they are beasts.I don't see so much of a problem with using a 530 chain on a 525 sprocket with regards load on the chain due to the wider spacing. The roller bears on the pin and you're not going to bend a 10mm diameter roller with Rd250 power so the pin should bear to load just as well. That said, it just doesn't seem right from an engineering perspective.
As pete says and I agree, I dont see that as a major problem if the sprockets are not worn how can it create extra wear you will probably find the chain is bias to one side anyway, most bikes are never exact.putting bigger (530) chain over thin sprockets (525) is apparently akin to pulling on a twig with your finger whilst someone holds the twig with their hands apart. Seems an extreme analogy when 1/16" space is the free-twig-space but basically I think it would wear the components quickly
Ha presumably taking the chain off first !!
you might get your thumb caught between the rear sprocket and the chain.