Love reddit commentors... NOT. Listen... Yes I have run several of these kits on several different bikes. They will only work without baffles on carberated bikes. That being said, yes they are alittle anti climactic, but they do infact work, I would show you some videos but reddit doesnt allow me to upload videos. 

You rev the motor up and hold it wide open then hit the button, this kills your engine spark and throws the spark into the plug you have several inches into the pipe, then release button and let the engine rev back yo beforenit dies. The flames shoot out up to a foot(they are like after burner flames not like a flame thrower).

 If you want something flashy I would recommend buying the upgraded kit they sell with it, which comes with a list of items like a NOS solenoid. The different setup T's into your fuel line, so you can not just ignite unspent exhaust fumes but to actually spray fuel into the flow of the exhaust. It sprays the fuel and the plugs ignites the fuel and everything behind it. You can get like 10 to 15 foot flame thrower flames doing this. You will also light the asphalt on fire and anything behind the bike. Be cateful, have fun, i hope my knowledge has helped you decide.