Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Belt idler pulley

[Karl]

Did you find the cause Douglas?? If you checked the idle pulley and that's ok then the other possibility would be, the stud failing due to the belt tension being too tight and putting stress on the idle stud. would check the conditon of the tensioner pulley and replace the locknut just in case.

[Douglas]

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?!

[rockhopper]

Its too early for me to work out the physics behind it but belts and things like that often tend to fail at low revs becasue the loadings on them are higher. My dad had an old Rover SD1 2.6 and that seiezed its cam shaft at tickover (twice actually but thats another story).
Years ago when i used to build Mini engines with hot cam shafts they needed to be run in at highish revs otherwise it was possible to knock the lobes off the cam.