Use Sprocket Specialists... They have every size front & rear for you. And the rears can be aluminum to save a little weight.... Also there is 415 size chain available that if you shave the sprockets you can use less power to rotate wheel... I use to race the early MT125R road racer that Honda sold back in 1977/78. Sprockets were the same mounts so there was a wide selection available thru sprocket specialist that if I had bought the Honda sprockets would have cost me the proverbial arm & a leg.
