JT sprockets are fine for the back but dont risk anything but the best in chains Tsubaki renthal did and the likes .
I bought my bike and it had a new cheap chain on it stretched like mad and broke after about 4k miles .I never have broke a good chain and they dont stretch .For the extra money its not worth being stranded .
These singles are particularly hard on chains .Forget alloy rear sprockets they dont last .
Go renthal front jt rear and a quality chain .
BANDC express have a full choice of sprockets and chains so i use them mostly .