wrong spark plug, or timing are 1st guesses, maybe incompletely plugged decomp.
also the intake that comes with the airsal kits is epic heaving shit. I have no idea why but it's significantly shittier than stock. like smaller diameter and the port doesn't line up with the cylinder, it's retarded. but that's not gonna make it go 30. I'm gonna guess 1 of those 3.
1, mayhaps your timing is way off (I run 15-20° BTDC, play with it in there starting at 17).
Also 2, the airsal kit NEEDS a long reach plug, using a B7HS will definitely cut your power by a shitload. ES only.
and 3rd, the decomp: stock ones leak a lot if you reused the old one, it's best to plug it entirely with m10x1.5 and make SURE the bottom of the bolt is bottomed out in the hole, not bottomed out at the cap which could leave the hole open.
Head leaks could be issue here too.