has anyone tried to build an airbox for the carb. i've heard that's where alot of the noise comes from and to me the quieter the better. any ideas would be appreciated, thanks.
Yes and yes but the details of course will depend on the engine you're quieting and how/where they are mounted. If you're referring to the China 2 strokes in-frame, which I do not use, then this will only apply in the broadest general terms.
If you are successful in quieting exhaust note, the intake noise becomes apparent. For study I suggest taking a look at how scooters are made. The engines are enclosed in a seat cowling with an airbox built in. I have a friend with a Yamaha Zuma 50cc 2 stroke and it is whsiper quiet.
A trip to a junkyard might yield some ideas, as it did for me, of cannibalizing the injection molded air intake ducting off of various late model, small engine cars that could be easily cut down or modded to serve the purpose without being in the way or god awful ugly.
hth