Factory tensioner works just fine. Seems most problems people have are from worn & stretched cam-chain. Which wears out tensioner quickly and replacing CCT results in temporary fix, but it'll wear out quickly due to stretched chain.
Since tensioner doesn't get much lubrication, might be good idea to take it out and slather with synthetic grease as preventative measure. Measure cam-chain stretch while you're there.
Related threads:
https://faq.ninja250.org/wiki/Cam_ch...sioner_removal - 300 appears to have more durable design, but still doesn't get much lubrication
https://www.ninjette.org/forums/showthread.php?t=109402