So im fixing this dirt bike for a customer. he said it wasn't starting. i took it all apart, cleaned carb, got it all back together, and it started rite up. however, it wont rev. it idles perfectly but as soon as i touch the gas, it bogs out unless i rev it slowly. it revs slowly though. in firt gear it run fine, but as soon as i hit second gear, it bogs no matter what. but again, it idles perfect. it got brand new gas, strong spark and a clean air filter. if i lean the air screw, it help with the bog when i first touch the throttle, but it way too lean. Any Ideas? its a 4 poke BTW.