I have a reoccurring issue with one of my belts. On the vertical (only) cylinder, the belt seems to move and rub on the inside edge (closest to cylinder).  My pulleys are in great shape (recently replaced) and the belt, itself, appears to be in great shape, too.  But the inside edge is obviously coming in contact, and abrading the belt, although VERY minimal.  The belts are less than a year old, and have about 2000 miles on them.  If it weren't for the edge issue, I wouldn't even think about changing them until next year.

Any thoughts as to why this is happening?  The same thing happened on the old pulleys and old belts.  Is this a normal issue?

Any help is appreciated.

-Chris

Never had this issue.  It sounds like you don't have the belt tight enough.  There is a measured amount of movement, or flex of the belt that you should get when pulling up on the belt between the cams.  I can look it up in my manual if you need me to.

Friend's 748 did this on a group ride. Belt snapped. He got lucky that the valves didnt touch the piston. I'll ask friday when I go over there what caused his. I think it was like thingy said, the tension was too low.

I would check out the Gate's website.  Gates is the original manufacturer of the HTD, curvilinear timing belt series used by ducati.  Here's a link to one of their troubleshooting PDF pages:  http://www.gates.com/facts/documents/Gf000287.pdf   Look at page 4 of this document.  Most likely what your experiencing is an angular misalignment issue.

I have not looked at your setup, and can't know for sure what kind of belt tension you're running, however, here's a blanket statement about synchronous timing belts:  Increasing tension will not improve its ability to "track", it will however decrease the useful life of all drive system components.  In fact, it's logical that a misalignment causing uneven wear will be exacerbated by increase loads (or tension) forcing the belt hard against the flange.

A timing belt is a compromise between a couple of issues.  1st there's durability, then there's the "timing" issue.  Here's another blanket statement:  More tension will enhance timing accuracy at the expense of durability.  Obviously this isn't always true, just as running the belt "whip" loose will not increase durability.  Gates recomments fitting a new synchronous belt approx. 25% tighter than a used one.  If ducati doesn't have a spec in their manual for both new and used belts, I would have no idea what their tension spec means.  Unless you own a frequency meter recommended by both Gates and Ducati, it is very difficult to manually set the tension "ideally" on the short-span, double idler drive setup found on the Ducati's.

As for myself, I check and adjust belt tension after every race weekend... and typically run it on the loose side, sacrificing a little timing accuracy, but knowing I'm not stretching the crap out of the belt as everything warms up and tension increases.  On the old 2 valvers, people have been using the 5mm allen wrench trick with great success for many years... it even seems to work on the new DS motors.  Not sure about the DesmoQuattro motor, but on the Testa motor, the idlers have flanges that make this trick difficult to pull-off.

As for fixing the issue?  Whenever you buy a ducati, I recommend a complete disassembly of the motor to fix all of their mistakes.  However, its possible that only the timing shaft bearings are cooked, unfortunately, you have to split the cases to change them.  So, while you're in there anyway, you can fix all ducati's mistakes.

Thanks for the Gates site link. Good info. I don't know the torque specs off the top of my head, but I know they are on there per the manual....which, thankfully, I have!  The crooked timing shafts sounds like the way to go. I'll post up more when I find it!

Good karma to all- thanks again, guys.

-Ski

what model engine are you running?  i had this problem on a 748 once someone had added a washer underneath the idler causing it to rub. can you see the belts while it's running?  and does the idler have a lip on both sides? i bent a idler stud on my 748rs one time when the plug wire when through the belt (don't ask) and it did the same thing. i doubt it's a tension problem ive run them too loose and too tight before with no problems. i run my 900 belts super loose and never had any problems

QuoteAny thoughts as to why this is happening?

because its a Ducati...

youre welcome

Quote from: tstruyk on February 16, 2010, 11:10:43 PM
because its a Ducati...

youre welcome

You complete me, Timmah.

GET A DIFFERENT BIKE CHRIS!!!

Quote from: backMARKr on March 11, 2010, 04:06:52 PM
GET A DIFFERENT BIKE CHRIS!!!

Can't afford to.  I really enjoy riding/racing the duc though.  It's different, and has some odd quirks, but I think that's one of its draws.

Quote from: skiandclimb on March 11, 2010, 05:35:20 PM
It's different, and has some odd quirks, but I think that's one of its draws.

Like being slow, heavy and clearly a lightweight class bike being forced to run against 750 and 1000 cc bikes? Sell that hunk and buy an 05 R6. It will be way faster, way cheaper, and we wont have to answer tech questions on a broken or about to be broken Ducati every 2 months. 

Youre welcome. 

I can feel the love!!!!!!!!...Or Ducati hate???!!!