Other then making it loud as hell, does removing the spark arrestor on a yoshi slip on hurt anything?

 

That's the beauty of a slip on such as yoshi or hmf, you can add a spark arrestor, or even a sound baffle, or remove them all together and run it as an open exhaust. On my yoshi I have ran it with just the spark arrestor and wide open, I haven't had the need to put in the sound baffle yet. Sound difference between spark arrestor vs. no spark arrestor is minimal. Theoretically, removing the spark arrestor will flow more exhaust so you may need to rejet. The nice thing about the yoshi is all it takes is 3 screws to change out the spark arrestor, there is even a paper gasket in there.