Q. I have two bikes, a Triumph Bonneville and a Honda CB1100. The Triumph's shop manual says to check the valve clearances every 12,000 miles, but the Honda's says every 8,000. They both use shims to set the clearance, and they're both low-revving air-cooled engines. So why the different adjustment intervals? A friend with a Honda Gold Wing says his valves don't need to be checked until 32,000 miles. Is that because it's water-cooled? I've read on Internet forums about riders who have never checked the valves, and their bikes run fine for thousands of miles. Is it really necessary to check them at all?