California has more than 830,000 registered motorcycles, and up to 85 percent of them have modified exhausts that are loud and polluting. Many of those modifications are illegal, too. Which is why two bills making their way through the state Legislature would mandate smog tests, either every year or every other year, for cycles built after 2000.
Smog checks for motorcycles - Press-Telegram
Smog checks for motorcycles - Press-Telegram