Ducati Monster Forum

Moto Board => Tech => Topic started by: chipripper on December 02, 2016, 09:02:19 PM

Title: Belt tensioner pulleys
Post by: chipripper on December 02, 2016, 09:02:19 PM
Sorry if this question has been asked and answered. I got to the belt change / valve adjust part of my 12000 mi maintenance session, and noticed my vertical cylinder tensioner pulley free-wheels maybe half a turn when I spin it with my finger. The other three spin smoothly, but stop spinning when I stop pushing them. My notes from the 6000 mile valve check said all 4 rolled smooth but did not free-wheel.

I searched and read several threads, about stuck pulleys, notably this one ->http://www.ducatimonsterforum.org/index.php?topic=3175.0 where Duckpainter said his do not free-wheel.

How do I know if a bearing has gone bad or is going bad? Should I replace it anyway just to be safe?

Now that I look at the photo, I notice grease around the inside of the suspect pulley, and the other 3 look dry. Maybe the bearing has lost its seal and its grease. ???

(https://lh3.googleusercontent.com/87o1yw_hzZgABOhCUw6irurLy7GWRTfi36eVj9Xj6LuYbaOj7xesPdaS6hz3Q66hq2hkLwQ7AIHDONsKzYXHtsV_gCjGKCv618SeVHak-WRxWAHYb5CQBRQCl9zn2X8pasRGBqeBAwMhX3fXCMk87qimrveZ1Wq_zKrXUAYQewgR2indN50NMiuMTF6uiGEp1hqS4i09OWvY5VW6f2OgTE7M1qAjbYFcxuFzzUtonEdHtKOvBBbmzDkofsKBNfqNf_oGglje1IuW4o6IO5CJ-2wF5lko5xTjCHm9wW3rZo6dyWbVpv2H3HIAM9k8yYXxKOeATGl3Q4kK4SVBmi51nOwPI7HZFmtkJGaj6pT0V5leprq6xIw7dYY_TofCM0VLik4iEkF1p98OzLSOwHDH_8V_5LUyefeu0LI8sCQdBLQB3Ng8VRdxqOfZbsKoVRO4bM_oqJ4GnC1PZxqiZx8aOBbAnQyHI2C66R5eHyti5R83sgKlUP1v4bNAC1sqttwUDkSxqV9DZXhFoWpRfMe3mb-ZwIqm6AqKCI_6m3VIb96agTLKhfDhqFVFdPnyUwiSLBSG1hIqM-eYlu_6QgKpKl1MxkFdy8MQlD35COnzSesqDFvc=w1267-h950-no)
Title: Re: Belt tensioner pulleys
Post by: Howie on December 02, 2016, 09:19:56 PM
I would change it.
Title: Re: Belt tensioner pulleys
Post by: Speeddog on December 02, 2016, 09:39:01 PM
+1.

(https://c8.staticflickr.com/6/5101/5858210167_b2d0647925_b.jpg) (https://flic.kr/p/9VERMz)
Title: Re: Belt tensioner pulleys
Post by: chipripper on December 02, 2016, 10:10:08 PM
Thanks for the responses guys.

Ouch! That pic looks like it could have been real bad for the valves.

I will pull it off the bike in the morning and give it a better look. Is it serviceable with new bearings or do I buy a new tensioner assembly? I saw a thread with a bearing part number but it was only compatible with bikes through 2006. Advice?
Title: Re: Belt tensioner pulleys
Post by: chipripper on December 03, 2016, 10:42:07 AM
So I removed the tensioner this morning and I don't see any c clips or any other method of disassembling the roller. It looks like one large bearing press fit onto the roller. It definitely has some play when wiggled, and sounds a little crunchy/dry when spun. GP has one in stock for 96$. I will probably get a new one and see if I can re-bearing this one as a spare.

Does anyone know where to get one at less than dealer price?

Has anyone replaced the bearing in this specific roller?
Title: Re: Belt tensioner pulleys
Post by: Speeddog on December 03, 2016, 11:50:35 AM
If it spins freely and makes noise, it's toast.

The three companions to the one blown-up roller I showed above were noisy and free spinning.
Owner was not happy about the replacement cost, but he did understand that he dodged a large-caliber bullet and he'd best not press his luck any further.

AFAIK, not a serviceable component, unfortunately.
Folks have searched and not found.
Title: Re: Belt tensioner pulleys
Post by: chipripper on December 03, 2016, 01:02:40 PM
Thanks Speeddog. Headed to GP now, to give them all my beer money. I will definitely reduce the interval for checking the rollers. I am very happy I decided to take my bike apart instead of riding. It is tough to do, since there is no "winter maintenance season" in San Diego.  :)
Title: Re: Belt tensioner pulleys
Post by: EEL on December 27, 2016, 11:48:42 AM
The most common reason for busted pulleys is improper tension. Mainly too much. Keep it at around 100 Hz for both belts.