What kind of rear sprocket do I need?

[xs650dreamer]

Hi 'dreamer,
520 chain is 2/3rds the width of 530 chain and thus must last only 2/3rds as long.
As the cost is also 2/3rds you break even on chain BUT as you should also change the sprockets and they cost the same for both widths you lose money running 520 and you get your hands dirty more often.
The sportbike boys run 520 to save weight and so long as the chain lasts for the practice laps and a weekend's racing they are happy.
And if you look up the recommended maximum power transmission rate for industrial #50 chain, it's good for ~5HP.
It's amazing how far modern chain makers have come.

530 is just too much for our bikes its heacy and our bikes dont make enough power to stretch those chains out fast, oring or not. everyone has thier own opinion and you just have to weigh pros and cons i run 520 and parts are alot lighter like you said chains have come a long way man