I have a 2005 suzuki vinson 500 LTF500F. I can not get it to start and stay running. cleaned carb, rebuilt carb, cleaned and blew through all ports with air gun. Only way to get it to half way start and run is to put hand over hole on air box and then it starts and will run for a couple seconds until it sucks the intake tube SHUT! You then can hear it sounding like a air leak after it stall out until the intake is back to normal. Anybody have any ideas?