Has anyone taken out the spark arrester and quiet core? HOLY HELL i took them out and went for a ride.... if my neighbors didnt hate me before they do now. Its SOOOO loud with out those couple things. Its too loud that the cops would bust me... i dont feel that its really obnoxious with the quiet core in... but with that stuff out it is more than obnoxious.

 

On the running a bike with performance exhuast and air box lid off hurting the motor YES it can I have seen the edges of valves melted off . If you just putt around not so bad but if you run the bike hard you will burn a valve and cause other problems Its not my opinion its a fact I have repaired engines that it happend to. You have to understand how a carb works and tune each area for your Mods Main jet Piolet jet, Air or fuel Mixture screw, Needle each one is as important as the other in tuneing at every throttle position.