New timing belts / valve adjustment interval? Miles vs Time

[metroplex]

My 09 696 manual says to change the belts every 24 months / 15k miles, and to check/adjust the valve clearances every 12 months / 7.5k miles. I don't ride anywhere close to these miles, so I am wondering when I should actually perform these tasks?

Does the timing belt go bad after 24 months? Do the valve clearances change by themselves?

I can log maybe 500 miles a year on the bike.

[TACstrat]

The service manual for my 796 has a footnote denoted by a (1) indicating "operations to be performed only if set distance interval is reached" (i.e regardless of time). Adjusting the valve clearance is one of them. Replacing the timing belts is not. Maybe the timing belts are like tires and become less pliable with time.

[He Man]

My 09 696 manual says to change the belts every 24 months / 15k miles, and to check/adjust the valve clearances every 12 months / 7.5k miles. I don't ride anywhere close to these miles, so I am wondering when I should actually perform these tasks?

Does the timing belt go bad after 24 months? Do the valve clearances change by themselves?

I can log maybe 500 miles a year on the bike.

Whats the point of owning a bike then? unless you like collecting them.

The reason for the belts time limit is because the material degrades as its exposed to different temperature and humiditys.

Even if you were to keep it in perfect conditions, i would still replace them. Mostly because you are probably allowing the belts to sit for a long time, they tend to take the shape of the cam after sitting down for a while.

In all reality though, your belts wont really snap even if you went pass the mileage and time by a few thousand or even a few months. But the damage is not worth the risk.

[Curmudgeon]

After 5 years you probably really should change the belts. Don't worry about the valves until 7,500 if it runs OK. Ducati is conservative regarding the belts for obvious reasons. They have no issue with you putting 15,000 miles on them in two years before replacement though.

The later belts, maybe on your '09, are Kevlar reinforced and have red lettering or numbers. The manufacturer rates these at 10 years, but not necessarily doing Ducati duties.

In "olden time" on my Pantah-based bikes, Ducati had no time recommendation. Those I used to replace when they started throwing "powder", (Lots of black "dust"), maybe every 3 - 4 years.

When I asked my dealer, master tech, about this, he indicated that the 4-valve bikes were a lot harder on belts than the two-valve bikes.

[Kev M]

I'm told by engineers in the field that a standard for part strength is three times expected load.

I never asked about how that relates to maintenance, but have always expected most recommendations are similarly conservative.

Therefore on certain recommendations I'll double the time requirement assuming I've not yet at least met the mileage requirement.

[He Man]

I'm told by engineers in the field that a standard for part strength is three times expected load.

I never asked about how that relates to maintenance, but have always expected most recommends are similarly conservative.

Therefore on certain recommendations I'll double the time requirement assuming I've not yet at least met the mileage requirement.

it varies A LOT.

if you use a number like 3, you knowingly admit that you dont really know when it fails.
a value of 2, means you know when it fails but you dont really trust the application of the load.
a value of 1 is you know exactly when it will fail and you know the exact load at which it will fail.

When materials undergo cyclical loading, it is not uncommon to see a 50% reduction in the load required to caused failure ( or a ratio of 2.0). cylical loading to damage is not linear, so if you increase the reducation to say 40% it does not mean you've increased the life of the component equally. All materials are a bit different.

therefore you cannot assume that if you have a reduced the load by 3 times, you can get 3 times the life out of it. You may actually get 5 times the life out of it.

As for the length of time, conditions vary too much to make a assumption on how far you let it go. If its mild temperatures and mild humidity, i will do 3 years without worrying too much though. Outside of that, its up to you. belts are cheap ($100 for a pair in most cases) and easy to swap. why risk engine damage?

[NAKID]

So, I've put ~17K on my bike since I had the belts done last April, they still look great, but I have to say I check them pretty regularly (after every ride, usually daily during the week). I also have open covers which makes this a bit easier. The new belts are the CA Cycleworks belts so I'm not really sure when I should start to worry.

[Kev M]

I guess I should add that my doubling of the time on some maintenance items (again assuming lack of mileage) is also based on two decades of professional observation in the field of vehicle maintenance and repair.

It also assumes my own personal usage and care which is on the gentle side of things, meaning little abuse and relatively mild temperatures.

It's also a very loose standard that I vary case by case.

That said, my research into belts led me to feel comfortable planning to change ours this coming summer.

[He Man]

So, I've put ~17K on my bike since I had the belts done last April, they still look great, but I have to say I check them pretty regularly (after every ride, usually daily during the week). I also have open covers which makes this a bit easier. The new belts are the CA Cycleworks belts so I'm not really sure when I should start to worry.

after seeing them lift thousands of pounds with the belt. im pretty comfortable running them 3years of 24,000 miles of moderate riding.

[NAKID]

after seeing them lift thousands of pounds with the belt. im pretty comfortable running them 3years of 24,000 miles of moderate riding.

I was hoping to hear something like that...

[ducpainter]

After 4 years and very few miles the belts on my 900 were more like plastic rings than pliable kevlar reinforced belts.

[koko64]

I reckon time has a bigger effect than miles, particularly if the bike is sitting around.

I just pulled some belts off an M900 that a dealer (interstate) said were changed as part of it's regular servicing. The bike sat around a lot, unused due to issues and the old looking belts had cracks and splits appear when you squeezed them in your hands off the bike which otherwise were invisible when on the pulleys.

[Kev M]

The more I read, the more I'm gonna stand by my four years, gentle usage, 7500 miles change interval...I'll let you all know for sure this summer....

[Howie]

Strength of the belt is only one factor.  Time, temperature, contamination, frequency of change in RPM and load, belt adjustment, frequency of start from rest plus many other factors I can't think of at the moment will all affect belt life.  Factory intervals are preventative maintenance, therefore conservative since the idea is to replace before failure.  I was working on cars with timing belts back in the early '70s when the common interval was 25K miles.  I also owned two of them, a Honda and a Lancia.  I saw cars with 100K, belt never changed.  I also saw many premature failures, including my two.  The Honda at 24ish K on the road, thank goodness not an interference engine and the Lancia while manually turning the engine to line up the marks.  That was an interference (like our Ducatis) engine.  If I started it up that morning it would not have been pretty.

If an individual wants to extend the interval and increase the risk, fine.  To advise others to do the same, IMO, is not so fine.

2014 Monster 1200 calls for a belt change by time at 60 months, 796 is still 24.  Difference?  Cam profile and timing maybe?  They just haven't got around to changing the interval for the older bikes?  Dunno, but I wouldn't want to find out by extending the interval on my 796.

[Kev M]

To be clear, I'm making no recommendations other than to explain my reasoning and, so far, my experience...ymmv

That said, even you admitted, factory maintenance intervals are CONSERVATIVE.