Karl, I havent really got to the bottom of it. I had wondered aboout an overtightened belt, but I set them very carefullly using the Hz meter method (110hz both belts), and they had done nearly 5000 miles when they failed, by which time the other belt had slackened off.
The other mystery was the very low revs at which the failure occured. Infact I hadnt used many revs on the bike for the last 1500 miles, as I was rideing with the wife, who rides pretty gently!
Any other ideas anyone?!
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