I agree, the sound is most likely a slight misfire and not that uncommon. There have been a number of people posting about a similar noise, they just don't align in describing the noise. It goes "clang, clang" or "ding, ding" or "clack, clack" , all descriptions of the same sound but each person with their own way of hearing and relating. The glitch can be low idle speed, resistor cap on a plug, a plug, the plug wire, a fuel injector, etc. There are lots of things that can cause an odd noise.
Does it start normally? Does it run well? Is the gas mileage way down? Do you notice it when riding? Does the engine turn off when you shut it off? Are there *any* physical symptoms beyond the noise? It may be time to employ selective deafness and just ride. Over time maintenance and perhaps a bit of injector cleaner will probably eliminate the sound and you most likely won't notice it's gone like you notices it's here.
But, if your CCT doesn't have a dot, change the sucker. You may start to hear a little rattling, then later a subtle, quiet little pop/bang noise and the engine won't start or run. A quick check will show 0 psi in all cylinders and you will have great regret that he CCT wasn't changed. BTDT.
