The sucking sound is a vacuum leak. A vacuum leak is un-metered air entering the engine causing the RPM to be higher than normal. Make sure the hose isn't cracked and that the fuel cap is on properly.
hey folks,i need help with my 07 honda recon atv,it's a trx 250,i started it and left it to warm up with the chock out,went back 10 min'slater it was idling about 2500 rpms,i checked the choke it is working like it should,it is also making a sucking sound from the gas cap vent when i shut it off,i checked the vent hose it is not stopped up and the throttle cable is working fine, i would be grateful for any help,thank you, hoot