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New belts every 2yrs/12,000 miles is BS!! I just replaced the stock belts on the SS this weekend at 12,205 and they were absolutely fine!! Yea yea, I know about the whole warranty thing...I'm just saying these belts are capable of a lot more. The factory belts were the red lettered one's with Gates written righ on the side. (replace with the same thing) You could still read my old belts. No dryness, cracking, signs of wear or fatigue ANYWHERE. But, for the peace of mind, I changed them. Oh well...
 

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I just figure better safe than sorry. The longest my ST2 went was just a hair under 12k miles, but they were five years old, as the bike sat on the showroom for nearly four years (the belts on it will be replaced at the 3-year/12k point in a couple of months). My 748's belts went a little under 6k miles in four years (I just changed those over the weekend). The belts sure *look* like they'd last a long time, but I know don't want to have one break on me.
 

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i think it's one of those recommendations that never get updated as technology advances...like oil and milage. i think you're correct that the new kevlar reinforced belts are capable of much more than 2/12 but it's cheap piece of mind.

just be careful that you don't get the wrong belt stamped with the correct part number as i have in the past. that could have cost me big time with nothing but a "gee, sorry" from ducati.
 

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What I don't quite understand is the 2 years thing. What is with that ?
 

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bevel450 said:
What I don't quite understand is the 2 years thing. What is with that ?
You are supposed to change the belts every 12,000 miles or two years, whichever comes first. I typically put on 12,000/year on my ST's, but I can see where a Superbike might not get ridden as much.
 

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belts & tension pulleys

I know someone that skipped the 18k service (6k interval) and discovered one of the two rear cyl tension pulley bearings was shot when the 24k service was preformed, hence the belt was nearly shot it's self--yikes!!

Note: the other (good) belt seemed to be near it's life cycle too (thin), now whether that's because the other belt was burning up and made the good belt suffer more I don't know. These were DucatiMotor 737.4021.1A (Gates PowerGrip HTD made in UK). And yes I could easily read the labeling (except the toasted one) but guaging by how much belt material is left on the outside of the brown (kevlar?) material (sandwiched between the notches and the outside of belt) well, I won't trust stetching beyond 12k. In this case the belts were discovered after 11,200 miles. Oh this was on a ST3.

Point I mean't to add to your post was I'll be checking the tension bearings every 6k.
 

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I'm still puzzled by the 2 yr / 6K (12k?) recommendation. I used to have (1984) a relatively small Opel (GM product in Europe) with a 1.6 OHC diesel engine. The cam and the diesel-pump were driven by the same belt which seemed very similar (width, thickness) to the belts on Ducati. Only longer. I'm assuming that life for this belt was much harder, albeit at lower rpm. Recommendation for replacement was 60,000 km, ca 40K miles with no "expiration date". The guys in the dealership called this over the top and said they replaced them at 90,000 km / 60K miles and had never seen a broken belt. Quite a difference. Yet I'm hesitant to go against Ducati's recommendation.
RonB
 

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I have heard the reason for the short replacement intervals is the small radius of the cam pulleys and the speed at which the belt is operating. On a car, the radius of curvature is much larger and easier on the life of the belts.

Mike
 

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+1 what ducati mike said.

also, i gotta believe that for liability reasons, they tell you to change them at the given interval even though they could go prolly a bit more (i.e.: built in safety margin). But at the potential cost of bent valves and what not, new belts are cheap insurance. Plus, it gives you another reason to work on your bike.
 

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Ducatimike hit on it. The 2 valvers have small diameter pulleys and idlers which cause the belt to flex a lot to accommodate them. This conforming degree of flexing hastens internal wear of the cords. Yet I have a friend who put about 8 years and 30,000 miles on his Monster with the original belts.

The testastrettas have larger diameter pulleys/idlers therefore belt life should be longer. But,, I'm not going to chance it. Belts are expensive, but umpteen times cheaper than engine guts. Trash an engine you pay I'll guess $4000 to fix it. How many sets of belts can I buy for $4000. 25?

I've seen broken belts on cars. Up to 10 years and 80,000 miles on them. Other than being broken, they still looked brand new.
 

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My belts had 8k miles and almost 6 years on them and one broke. I accpeted it as my fault for pushing the belts soo long. Piston slammed into the valves and bent the valves, cracked the guides. I got off cheap. The damage of a broken belt can involve the bottom end. Including the big end bearings, crank and or rods. Yeah the 2 year/6k miles are on the conservative side. Now that I have built my motor into a balanced and blueprinted 853, guess what? Belts are getting changed every 2 years. Its cheap compared to a motor build. Unless your like me and want to use it as an excuse to trick out a 748 into a bad ass 853.
 

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Discussion Starter #13
Oh trust me, don't get my post or my intentions wrong...I agree with everyone, BUT, I bet the capabilites of these belts, barring any other mishaps (bad rollers, neglect, etc) safely exceeds 20-25,000 miles.
 

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I've been on the bad side of a blown belt, on VW GTI. VW recommended a new belt at 75K miles, it failed at 72K. A 2" long section of teeth separated from the reinforcing belt at the crank pulley. The belt stopped, the valves stopped but the crank was still spinning. All the intake valves were bent. VW claimed out of warranty, but they had sent letters to 1 year newer model owners, down grading the belts from 75K to 60K. They eventually paid for it, but it was a couple of weeks in the shop and it never ran right afterwards.

Moral of the story: Belts are cheap.
 

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Ok, I can handle every 12K miles, but what about the 2 year requirement? What if someone only rides, say, 3500 miles a year? That'd be around 7K miles after 2 years which is just over 1/2 the mileage spec. If it were you, would you still replace @ 2 years or would you go for another year? Personally, I'd go for another year.
 

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Now you're talking !

Yes, this is EXACTLY the issue that I was addressing....hey, the mileage thang is obvious, right ?.......so why change the belts on a bike that is seeing minimal mileage ? Or, if you please to make the point, a bike that has sat in the garage and not ridden for two years.

What is the issue with two years ?

Two years seems ridiculous unless there is some issue about maintaining the belt under static tension stress over time.

b.

1999r1 said:
Ok, I can handle every 12K miles, but what about the 2 year requirement? What if someone only rides, say, 3500 miles a year? That'd be around 7K miles after 2 years which is just over 1/2 the mileage spec. If it were you, would you still replace @ 2 years or would you go for another year? Personally, I'd go for another year.
 

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I think Ducati is so paranoid of belt failure that they have cut the lifespan recommendations in half, then half again.

For a racebike that spends it's life at the limiter, I could see it but a streetbike? Nah.
 

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galaxy said:
Oh trust me, don't get my post or my intentions wrong...I agree with everyone, BUT, I bet the capabilites of these belts, barring any other mishaps (bad rollers, neglect, etc) safely exceeds 20-25,000 miles.
Let us know when you get to 25,000 miles. ;)
 

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1999r1 said:
Ok, I can handle every 12K miles, but what about the 2 year requirement? What if someone only rides, say, 3500 miles a year? That'd be around 7K miles after 2 years which is just over 1/2 the mileage spec. If it were you, would you still replace @ 2 years or would you go for another year? Personally, I'd go for another year.
I'm changed them on my 2002 748 with just under 6k miles on them....but they are 4 years old. Since I was in there doing the valve adjustment, anyway, I figured I'd change the belts for peace-of-mind, but also because I know that certain sections of those belts were bent over the sharp cam radius for over seven months without ever being moved. I don't like the idea of the belt being stressed that way for that long of a period (my bike was off the road from May of 2004 to May of 2005 with a single track day in Oct of 2004 being its only use during that time)........on the other hand, my 1998 ST2 was bought brand new in Sept of 2000, close to FOUR years old (by production dates), and I didn't change those belts until 11k miles later......two years later.
 

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Belts become brittle and weak over time due to regular decomposition of the materials. Just like your helmet liner. Just like tires, or any other rubber or synthetic rubber/plastic anything. It's no different. All plastic and rubber compounds decompose, dry out and shrink over time. Have you ever wondered what the heck that insidious "haze" on the inside of your car's windshield is? Within days of 409-ing the sh*^% out of it for the umpteenth time?? No, it's not cigarrette smoke. It's the plastic in the dashboard decomposing. It gives off fumes. Nice, huh? Well, unfortunately it's true.

Ducati's making what they feel is a very safe, conservative judgment call, based on the fact that they don't know, nor can they test, the accurate potential lifespan for your particular location, environment, riding style, etc.

You could argue that time is actually the most critical aspect to wear for a belt. Regular use keeps them from drying, becoming brittle, getting "flat spots", etc., but time ravages them, particularly if you live in a harsh environment. The expansion/contraction alone from swings between 100 degree summers to -10 degree winters just sitting in the garage will seriously accelerate wear, for example. Sorry, Chicago-ites! If you're lucky enough to live in a moderate climate, everything will wear considerably slower than in other places, but Ducati's got to provide recommended intervals for bikes that live everywhere from Helsinki to Los Angeles.

In the end, it's cheap insurance to change them, so the argument's virtually irrelevant, right?
 
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