Saturday, February 11, 2017

Ducati timing belt failures and replacement intervals

I thought I’d do a piece about belts as there’s a thread going on MS at the moment with responses from people who weren’t there when the shit went down and so don’t understand why.  I’ll try to clarify it from where I saw it.

The first reference to replacing timing belts based on time as well as km that I can find in any of the scheduled maintenance charts in the factory workshop manuals is 1999 996.  For the 1999 MY I also have ST4, M900 and 750SSie manuals, and none of those have it.  All the 2000 MY manuals have an * after “Timing Belt” on the chart and “(*) Replace every two years, in any case” at the bottom of the chart.

As to whether there was a service bulletin about the two year thing, I don’t know.  I have quite a lot of Ducati service bulletins, some back to 1990 or so, but nothing on belt change interval, nor a listing for it in the index.

The first broken belt I saw was in 1995 or so, a 900SS that came in for an opinion to be used in a court case against another dealership.  Typically of the very few 900 that I have seen with broken belts, it also had a loose vertical cam pulley.  As in flogged out and flopping around.  It went again without us touching it.

I think I saw one Pantah with a broken belt.  Asking the owner when they were last changed just drew a blank look.  It got a new belt and was fine, one of the few.

I recall Rob doing a head that was bought in, probably in late 1997 or so as I recall it being in the then new engine room, from an 888 that had broken a belt.  Didn’t know anything else about it though.

The first broken belt we were really involved with was a 916 owned by a friend of Rob’s.  Sold mid 1996, with the 10,000km service done mid 1998 around two years old.  It broke a belt a few months later at a Moto One Broadford track day.  We got it back to work on the Monday after, pulled it apart and found the horizontal (almost always the horizontal) belt broken.  You can tell if the valves are bent by trying to rotate the cams.  If the valves are bent, they pull the closing rockers down and jam them against the cams, thereby stopping them.  Simple check.  I recall one 916 coming in that we fitted new belts too and away it went.  Only one that lucky.

We rang the importers and got asked “why weren’t the belts changed at two years old” and we asked “why do they need to be”.  Then the typical “well, it’s all your fault because .....” that we heard quite a few times from importers over the years.  I don’t recall ever hearing anything about two years before that day, nor seeing anything from Ducati (service bulletin, etc) saying it, but the message from the importer was very clear.  Two years, no more, no help because the warranty’s up.

That was the start of it.  Probably averaged a couple a month for the next year at least.  748 and 916, 10,000 – 15,000km, 2 ½ to 3 years old.  Owners would come in wailing and wanting warranty, us explaining the Ducati line and the fact it’s out of warranty, us getting abused because somehow the mechanics at a dealership half way around the word from the factory are responsible for any design shortcomings.  All that stuff.  We were the preferred warranty dealership in Melbourne it seemed.  When the warranty claim rejections were faxed back and the owners informed, the bikes got picked up and went elsewhere to be fixed because we were too expensive, arseholes, etc.

Of course, while the message from the importer was simple, their own dealership compounded the issue.  We harassed every owner who came in with a bike from then on to replace the belts at two years old.  Everyone.  But we had customers who would ring up Fraser Motorcycles in Sydney and ask their workshop and they’d get told “we just look at them, and if they look ok, we put them back in”.  Then they’d come back in to us and tell us again we were arseholes trying to rip them off, etc.  The usual, with a new slant.

So we started putting “Timing belts not replaced at owner’s direction” on invoices.  Owners would see that (we’d usually point it out to them) and realise we were serious and if it did go bad it was their problem.  Then they’d get the shits because we didn’t tell them enough to convince them that they really did need to be replaced.

I can recall still getting phone calls into 2001 or so from owners at Philip Island track days.   One guy, who I knew we hadn’t seen since his first service in 1996 or so, had his 916 drop a cylinder down the front straight.  Turns out his bike had only done around 6,000km and probably hadn’t been serviced since the first service because there was no annual service regime back when it was new.  I gave him the usual advice: remove the belt covers and check the belts, the horizontal one is probably broken.  Unfortunately correct.

I saw one 851SP3 do it, and again it was a case of the owner being told, when he bought the bike second hand in 1996, that it was good to go until 20,000km.  I think I saw one 916SPS break a belt, I’m sure I had a 1998 model apart for that reason (no Ti rods!) and one 916 that did it within the warranty and belt life period, but there were some other potential concerns about that bike anyway.

I don’t recall a 996 doing it, and I think that’s because the new “red writing” belts with Kevlar in them were introduced with or around the time of the 996 in 1999.  I forget now.  And we were harassing everyone to replace belts at two years, so none of the bikes we serviced would have gone much past two years anyway.

In hindsight, the whole thing was handled poorly from an administrative sense.  BMW (who we were also dealers for, and who had time based service schedules) would’ve sent letters to all the owners pointing out the two year deal.  Of course, a lot of them would’ve been ignored until the bang came, but at least they had been warned.

The belt that caused all the issues was the Gates T917, which was originally a Renault belt.  Why it all started going bad in 1998 I don’t know.  Maybe it was the simple increase in sample size, with a lot more 4V bike sales, coupled with the increase in track day participation.  Nothing else changed in terms of engine design or layout.  Once that belt was out of the official spare parts system, the problem was effectively fixed.  You could still buy them via Gates, as we did for the Pantah and 900 belts, but we mainly kept away from the T917.  All the Gates parts numbers for Ducati timing belts were cancelled last year (in Australia at least), so now they’re gone for good.

There wasn’t an issue with 2 valve bikes simply due to a bit too old belts.  Very old belts yes, but not like the 4V.  I have had my own 2V bikes go 5+ years simply due to forgetfulness while still in use.  Nor is there an issue with the later models.  I have seen the occasional broken belt since.  I had a 1098 come in that had nothing but fluff on the horizontal and strands with teeth on the vertical, but it had at least one seized roller and I suspect hadn’t had a belt change in its 52,000km life.  The damage on that one was quite amazing.  The valves were Z’d (bent above and below the guides), and I couldn’t get one of the inlets out.  The inlet cam had flats on the noses so beautifully precise it looked like it’d been held in a fixture and stamped with a machine, with the material flared out both sides evenly.  The piston was also damaged, with a crack through the skirt into the pin boss.  Probably the first time I’ve had to do anything with a piston when fixing valves bent due to a broken belt.

But, due to professional paranoia and liability, we hassled everyone to replace belts every two years on all models, as Ducati directed.

Now they have moved the replacement interval out to 5 years on new models.  The MTS1200 and Diavel use the same belt as the 1198, etc.  Maybe, in the main, the SBK models get used a bit harder than the tourers rpm wise, but some of the MTS1200 get used pretty hard and often.

My question about that was, given the warranty is two years, what happens if a belt fails outside the warranty, but within the service time frame.  The answer to that, in the current Audi ownership model, is simply that someone other than Ducati will be paying for it.

I recommend 4 years at least with the genuine and California Cycleworks belts.  I don’t go over the mileage intervals, but again they’re being stretched as time goes on too.  What was only 20,000km became 24,000km and is now 30,000km, with no checks or re-tensions in between.  We used to re-tension belts every service, now you don’t look at them until the replacement time.  And with the massive increase in the amount of time required to just access the belts on some models – MTS1200, Diavel, even the M696 – 1100 series, it’s not easy to have a quick look.

Nowadays lots of owners who didn’t experience any of the belt drama back in the day question the two year thing, and many like to claim it’s a money making exercise, etc.  But the basis for it was a real problem for some models, and cost many people quite a bit more than the price of a set of belts.


everydayscience said...

Really interesting stuff Brad. I came into Ducati ownership after the belt failures but figured there must have been a reason why it was so tightly specified. Also matches with my 2V experience that you can let them go a bit longer time-wise than 2 years, even flogging them at trackdays. Something to do with the angles the belts are being turned around in the 4V coupled with a new construction in the belt that just meant they didn't last?

No matter the reason for it, thanks for the timeline/history of it!

Unknown said...

Hi thanks for article very informative,I have owned Ducati's for many years,I have a nice collection of bevels,2v and 4v.
I have changed belts around the three year time,All bikes have been ridden under normal Road conditions,with no problems.
I've just put a Gates T917 on my 92 851,The old belt taken off was a Ducati belt,red lettering but had next to Ducati Made in UK by Gates.Now that Ducati belt was 3x more expensive than Gates ones installed.Im happy to use Gates on 851 this bike will do approx 4,000 miles a year.
I'm interested to know your article mentions Gates belts in a negative sort of way,Did these belts fail due to high mileage,harsh riding etc.
Also what is your opinion on DAYCO belts as at one time I would not have entertained them but after speaking with Duc enthusiast's on continent they cannot see why I don't use them,as they are far cheaper In price than belts marked DUCATI but made by Gates.
I have now put DAYCO on my ST2 and 907
Many thanks Timbo DOC GB -Wirral Branch Rep

carrini said...

Great article.
I have just replaced the belts on my S2R 800 for the second time (after 10 years and 15,000 klm). For the interest of other owners the original belts were replaced after 6 years and 12,00klm. My service handbook specifies a belt change at 20,000 klm. No mention is made of a time period. Is this over servicing? I suspect it is but given that no-one really knows how long the belts will last, at $120 for the belts (I changed them myself) it is a no brainer. I expect I will change the current belts in four or five years time and at the current usage rate the bike most likely will still be under 20,000klm and therefore, still not require a belt change (according to the Ducati service handbook).
On this same topic it appears that there is no way of determining when the new belt that you are about too fit was actually manufactured. It could already be two years old.

JakeNicholls said...
This comment has been removed by the author.
tanken2 said...

10 years on 848 belts?

Unknown said...

Thanks for the information Brad!

I own a Multistrada 1100, 08' model. Bought it used 4 years ago with 41K kms and using it mostly for commuting - about 20K kms yearly. The bike is never abused, and is usually ridden mid-rpm, far from redline.
The bike has now 120K km on the clock, and it still runs quite well. I change the oil every 8K kms, and on this occasion I also adjust cam belt tension if required.
I change the belts together with valve adjustment at 24K service. Using ExactFit belts, I see no wear on the old belts. I feel a bit dumb replacing a part which has no visible signs of wear.
From your experience:
1. Do you think the cam belts fail because of time or mileage? How safe it is to run the belts for 40-48K kms in 2 years?
2. Every 24K kms my exhaust valves require adjustment - from maximum setting (I aim to a bit above 0.15mm) to minimum or a little bit below that (0.10).
Is it normal behavior for Ducati 1100 engine? Or it is sign of a problem?

Thank you,
Multistrada 1100,

Vivim said...

Really Good tips and advises you have just shared. Thank you so much for taking the time to share such a piece of nice information about Ducati Maintenance. Looking forward for more views and ideas, keep up the good work!

Lyder Moen said...

Hi Brad.
Thank you for very useful information.

While working on my 996-SP, modified for racing with a SPS head, i find the original positioning on the tensioning wheel to be insufficient for maintaining belt tension.
With a new belt, the tension need to be at maximum, and the distance between the belt while running between the rollers is almost down to zero.
-Actually on the older belts I replaced, I could see the belt teeth had been in contact on the horizontal belt, but not on the vertical.
I rode the bike for 1 week in February this year at Jerez-Spain reaching 1200km at the track starting with freash belts.

When looking at the belts after that, they where really loose, and not possible to tension up due to lack on cam-action by the tensioning rollers.

I have now removed the outer and inner covers, and made new adaptor brackets moving the tension wheel a bit up and to the left from its original position. This gains approximate 1cm distance between the belts between the idlers, and I can fully maintain tensioning.
-Moving the tensioning wheel is not feasable with the covers on, so they have to be left off permanently. For the race bike its fine, and adds cooling ability.

-I wonder if the poor tension was a part of the problem on the early 4V engines?
What is your experiences and advice?

Thank you.
Lyder Moen.

Unknown said...

i have been a respected motorcycle technician for 48 years now and have worked on ducati's since 1986...all i can say is dont be cheap and replace your cam belts every two years or 24000 kms !..just do it or risk having them break and destroying your motor and believe me when i tell you that you wont like the size of your repair bill