| It really depends on the circumstances!
If you have a bike doing a lot of miles, you obviously want to check and replace them more frequently than one that is stood idle.
I once bought an engine from another race team at the end of the season and we gave it a service before fitting it as we knew it hadn't been done since the middle of the season. When we opened it up we found one of the belts was split approx 3/4 of the way across from rubbing on a piece of gravel that hadn't been removed from a trip to the kitty litter a few races previously! Had that gone out on the track a few more times, who knows what would have happened!
Similarly, my Hypermotard did nearly 12,000 miles last year and the belts I took off for it's 2-year service were in really good condition and could have easily gone back on. I've just replaced the belts on my 748 which did zero miles last year, and even these were in really good shape and not deformed at all, so could have been used again too.
Personally, past experience tells me to check the belts every year for both tension and damage when I'm doing the oil change and to replace them every two years regardless. |