I had a Ford Escort once and I must have gone through three timing belts in less than 100,000 miles. Fortunately, the valves cleared the pistons. My '68 Galaxie had a 390 and at approx. 120,000 miles the timing chain started jumping. Funny thing was it would skip a tooth, run like a dog and sometimes die, and then it would skip back to normal and run great. Needless to say I couldn't continue to drive it this way as it left me stranded more than once. I prefer chains or gears for driving the cam(s) although a belt driven primary can be a nice thing. I better shut up now because I'm straying from all things Guzzi.