Duc peoples..a belt question

[skiandclimb]

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

[Thingy]

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.

[Woofentino Pugrossi]

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.

[123user]

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.

[skiandclimb]

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

[Ducmarc]

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

[tstruyk]

Any thoughts as to why this is happening?

because its a Ducati...

youre welcome

[skiandclimb]

because its a Ducati...

youre welcome

You complete me, Timmah.

[backMARKr]

GET A DIFFERENT BIKE CHRIS!!!

[skiandclimb]

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.

[benprobst]

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. 

[duckracer996]

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

[skiandclimb]

Probst,

Breathe, brother, and repeat the following mantra- "It's ok to be different, it's ok to be different."

Smooches,
Kuhn

[Gino230]

I had this problem on my brand new 1000DS. One of the pulleys was misaligned. That would be the first thing I would check.

[skiandclimb]

Thanks Gino.  Hey, whats your take on that DS? I have been thinking about retiring the aging 996, and going that route. I hear the reliability is better, and I can run more classes, but I also hear it is a beast to get the suspension dialed in.... thoughts?

Cheers,
Chris

[backMARKr]

Thanks Gino.  Hey, whats your take on that DS? I have been thinking about retiring the aging 996, and going that route. I hear the reliability is better, and I can run more classes, but I also hear it is a beast to get the suspension dialed in.... thoughts?

Cheers,
Chris

Chris...I have a plan for you......


(1) get in car
(2) drive to Ben's
(3) buy SV Superbike (pretty sure he still has one of Hernan's sitting over there)
(4) ride bike for two to three seasons in the 3-5 classes its legal for each weekend
(5) No more EYEtalian bike problems
(6) Check the "unique" box, in that the only thing "normal" is the frame --- the rest of the thing sure isn't run of the mill

http://www.ccsforum.com/index.php/topic,23964.msg193977.html#msg193977

[Ducmarc]

damn Gino your right on top of this thread lol.  i've been thinking about a 749r as an up grade from my 748r  would be the ticket in Tbike and f40 if your that old . they have all the good stuff from the start and there fairly reasonable. sneak in some big slugs and ride the middleweight classes

[Gino230]

Thanks Gino.  Hey, whats your take on that DS? I have been thinking about retiring the aging 996, and going that route. I hear the reliability is better, and I can run more classes, but I also hear it is a beast to get the suspension dialed in.... thoughts?

Cheers,
Chris

Chris,

I have a 996 track bike as well, and love it. Problem is it's not competitive anymore.

The 1000DS is a great racebike, very reliable, handles well and not many bikes are faster for the LW classes, unless you are going to drop $30K on a Bimota.....

I kept mine stock so I could race LW SuperSport, I put slip ons, GP chain and sprockets, STM breather (requires some kind of custom breather box or your airbox will get coated with oil), a K&N air filter and made 92 HP on the dyno with the airbox opened up. With the stock (SS legal) airbox cover, it's more like 88HP.

I raced on stock suspension for years, all I did was raise the rear to the max (if not the stock exhaust collector or pipe will drag). As I got faster, I had the shock and forks re-sprung at GMD, and added the longer end to the stock Ohlins shock to raise the whole bike.

All I have done in 5500 race miles (6 years) is 4 valve adjustments, 3 or 4 sets of belts, and one exhaust valve guide. I added a power commander a few seasons ago, it smooths out the powerband a bit.

Handling wise it's no 996, the chassis flexes more and it requires some more effort, but mine has never been crashed and handles very well. Fast enough to win at Daytona!

If you decide to go the 1000DS route, let me know, I can give you my geometry measurements so you can have a good baseline setup to start with.

The shop I work with, Moto Corse Performance, has put together about 20 of the things, and a bunch of 800's too, so I've benefited from all the tricks. You can go crazy with these bikes and easily get 100+HP, but I always figured there  was more time to be made by improving my riding so I left well enough alone.

Others on the board recommend alot more maintenance than I have done, but my experience has been that it's just not necessary. I can only give you my experience which has been very positive.

SV's can be made to perform pretty well too, and I've heard they handle just as well. My brother had a pretty well prepared supebike SV and I prefer my bike. Faster and well, it's a DUC after all!

I would love to campaign a 748 or 749, but they are really only good for one class, Thunderbike and LW F40 so I prefer the 1000, I can ride in 5 classes and be pretty competitive in all of them. My SS legal motor makes it tough to compete with the fully prepared superbikes and such, but a better rider could keep up....

[Gino230]

damn Gino your right on top of this thread lol.  i've been thinking about a 749r as an up grade from my 748r  would be the ticket in Tbike and f40 if your that old . they have all the good stuff from the start and there fairly reasonable. sneak in some big slugs and ride the middleweight classes

I'm with you Mark, sounds like a cool idea. But I wonder how much better it is than the 748R? And the 748/996 is just the coolest looking Duc IMHO of course....

Me I'm going to hang on to my 996 until it's legal for MW or 748 is legal for all the LW classes, then I'll hunt down a 748R motor. I just love that chassis I guess.

Then again I rode Chris' 1098R, that's no slouch either.....

[Ducmarc]

i think the 749r motor in my chassis would be the ticket  but as much HP Chris gets out of his I'm not sure it's Worth it. i can't out ride it now anyway plus it's paid for sometimes though you want something new, then  the boss brings me back to  earth

[chillydogg]

Hey Gino,

How did you have you SS set up?  Are the fork flush or dropped in the triples?  Is the shock length fully extended?  I have heard different setup stories where some people knife them out and some people raise the whole bike.  What's your preferred setup?

[roadracer162]

I'm with you Mark, sounds like a cool idea. But I wonder how much better it is than the 748R? And the 748/996 is just the coolest looking Duc IMHO of course....

I'm with you Gino, I like the look of the 748/996. And yeah Marc's 748 is one fast bike producing some 120hp as tested at MotoCorse. I must say that it is as quick as that fast Bimota and the last I raced it at Homestead it gave that rider some fits of anxiety with that much power. Sadly I did not have the skill to unlock all it's potential.

Chris has told me that he gets some 130+hp out of his RS and I believe it. I think the 996 is a great ride and with some performance mods could give the competition something to think about.

Mark

[roadracer162]

Hey Gino,

How did you have you SS set up?  Are the fork flush or dropped in the triples?  Is the shock length fully extended?  I have heard different setup stories where some people knife them out and some people raise the whole bike.  What's your preferred setup?

My 800 was set-up using the measurements taken from Gino's bike. What I have is essentially the 1000 adjustable forks and Ohlins rear shock with the shorter extension. The forks are set in the sotkc location with the clip-ons above the triple and pretty much flush. I can take more measurements if needed. The rear shock length measrues around 13 3/4"  from eye to eye with the weight of the bike on it without bodywork. I hope that gets you in the ballpark.

For me switching to the Marchesini aluminum wheels  translated in a big difference in turn in and just seems a lot better overall. With the stock 800 wheels I had trouble getting the bike leaned over onto it's side and thereby missing my desired turn-in. There are many that raise the whole bike or raise the rear but I find this geometry desirable. I did notice that with the ohlins shock the rear was taller by about one inch over the stock Sachs 800 shock.

Mark

[Ducmarc]

read my lips, monster triple clamps  and mr boy's makes over 140

[roadracer162]

I'm only going by what he tells me. Well I have some changes that I am making to the 800 trying to get into a more comfortable position on the bike. I don't know if I need the monster clamps because the handling is great.