STOP please.im 6'2" 205 but the rpm run kinda high. I have done maintence on it so Idk where to go. I though about putting a 42 tooth back sprocket and new twin brothers exust system and new air filters.
You have a small engine that is trying to haul a lot of freight......and it's pushing a lot of air at 70 too.
It NEEDS to turn a lot of RPMs to develop the horse power necessary.
You will be sorry if you change the gearing any more than you have already. Same for screwing around with the engine.
If and when you just can't STAND the way the bike runs or the gas mileage that you are getting........trade it in for a 650 or bigger.
And to repeat: You seriously should NOT mess with the intake or exhaust. You will be sorry.