"Hissing" and "bubbling" is not normal. There's 3 o-rings in there you should be worried about. One is in with the filter, and then there's one each on the hoses going into the pump/regulator assembly. Make sure all 3 are present and working correctly.
Check your spark plug wires make sure you dont have them reversed after taking the spark plugs out to check them seems stupid but a very common mistake causing the coil to misfire and get the bike to basically want to start but never will