I know its a dumb question but what is a Spark Arresetor? What does it do? Is it a good or bad thing? Why do some exaust kits come with them but others dont? Its a dumb question but how can you learn with out asking dumb questions every now and then.

 

First of all there are no dumb questions, only dumb answers. By the way the word is arrestor.It is a baffle within the silencer which arrests the sparks emitted as a byproduct of the exhaust. Spark arrestors are required in many states on public lands and also on many National Forests and the reason is obvious with all the forest fires recently. If you ride entirely on race tracks, a non-arrestor pipe is ok; otherwise we all should use an arrestor whether required or not.

 

RaptorRules is right it is a device to stop sparks from exiting your muffler. (ushaly a screen)