So i should leave the rear sprocket alone
gearing works like this 1 tooth up front works as 3 teeth in the back so if you got a 14tooth front it would be the same as putting a 37tooth on the rear (which you cant do without another sprocket holder) it would be a good idea to change both sprockets and the chain at the same time so they wear the same. i would get a stock replacement rear which is 40t and get a +1 front sprocket which is 14t that will gain you some good top end while not completely sacrificing your acceleration.
Gramer and punctuation is GOOD. for the airbox remove you lid and run an aftermarket filter like what comes with your b1. a 14 tooth front is also a good investment
Gramer and punctuation is GOOD. for the airbox remove you lid and run an aftermarket filter like what comes with your b1. a 14 tooth front is also a good investment