need more speed

ok that plus a set of reeds and you should have plenty of zip... id go and get a 14 tooth front sprocket that will give you plenty more top end but wont take all your acceleration
 
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.
 
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.

Stock rear 40's are really heavy, If you want alot of acceleration, you can get some really light weight sprockets from renthal..They weigh about half of what stock is. They last longer too.
 
if you are wanting more speed, stroke/BBK with porting and head cutting is the big combo that will allow you to go swimming with the shark. till then you are still sitting on the beach getting your feet wet.
 
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

Spelling is also good; grammer. You will be fine with a 14t front sprocket... you really can't push much more than that with only an exhaust upgrade.
 
i run 15/40 gearing and the blaster is still snappy as hell!!im bored .040 over, carbon fiber reeds, and pod.. otherwise stock pretty much, but she flies.. with some porting,pipe,carb,bigger tires, and gearing you should have some topend..