Biker 101: We have all heard the roar of a group of bikes arriving….. Are those loud pipes legal? Technically, no, but the law is rather vague. Texas Transportation Code 547.604 states that “A motor vehicle shall be equipped with a muffler in good working condition that continually operates to prevent excessive or unusual noise.” “Excessive or unusual” is left up to debate. You probably won’t be stopped and ticketed unless you are being really obnoxious about it!