Lowest rear sprocket tooth count for Bashan Storm?

[JTridesbikes]

Hi All

So several months ago I upgraded my rear sprocket to 42t and I did get a higher top speed but recently I upgraded to a new carb and I lost that top speed. My question is what’s the lowest tooth count I can run in the rear sprocket without running into any problems?

P.S. I’m already running 17t in the front

Thanks