One of the things that surprises me when I write posts are the reactions I sometimes get, specifically the questions that often leave me wondering how people interpret or comprehend what I've written. It makes me realise how hard it can be to be clear and get what I'm trying to say across. Compounded by my tendency to ramble and digress and straight up forget what I was rabbiting on about in the first place. So I'll put in some more belt info, and try to respond to some of the comments and questions.
Another thing is that (especially with cam timing) people ask me for "the good numbers", as if there's some sort of secret squirrel component to what I write. There's not. What you see is what you get.
The old Gates belts were available for all the Ducati models pre 98 external to Ducati via Gates distributors. The three part numbers were "cancelled" in Australia last year, not sure about the rest of the world. They were all differing construction types, which I found a bit interesting.
T934: the 900 round tooth belt - 900SS, M900, 906, 907, ST2. 1st generation construction, NEO - Neoprene rubber fibreglass tensile cords and nylon tooth facing. Interesting that the belt introduced last was the most basic construction. Never gave any issues.
T819: the Pantah square tooth belt - all small blocks (non 900) up to 1997. 2nd generation construction, HTN - High temperature neoprene rubber, fibreglass cords and nylon tooth facing. Never gave any issues. When the Pantah was first released, they had Pirelli belts which were rubbish I'm told by people who worked on them. And gone before my time. I have also seen Continental belts fitted to these motors.
T917: the 4V belt, also fitted to Renault R19, which ran from 89 - 96 according to the Gates book. 3rd generation construction, HSN - Highly saturated nitrile rubber with aramid fibre loading, aramid or high tenacity fibreglass cords and nylon tooth facing. The problem belt (from 98 onwards at least). The interesting thing is the aramid part. Aramid is a generic name for what is better known by name brands such as Nomex and Kevlar (both owned by DuPont). So these belts it appears had a Kevlar component, which was allegedly the big point of the red letter belts.
So to clarify, the only Ducati belt made by Gates that gave any issue was the T917 - available via Ducati or Gates. And the issues only appeared as a consistant problem in 1998, by which time Ducati seemed to have realised there was an issue as the "2 year replacement" directive was communicated to the importer (ours at least) before we had experienced it.
Why there was an issue I don't know. Lots of theories were expounded, but I like facts backed up with evidence and there didn't seem to be enough of that to generate any conclusions. Lots expired down the front straight at Philip Island, but lots didn't. They just broke on bikes that were more than 2 years old, but had done less than 20,000km. We also saw belts break that had been fitted at 20,000km services, but not replaced again within the 2 year window. Yes, the pullies are quite small compared to most automotive applications. And, on the 4V, there are quite extreme changes in direction compared to what you see in most automotive design. But, anecdotal evidence of belt life before and after, especially with the later belts, would indicate that the actual engine design is not "the" issue.
The Red Letter Belts, or whatever you wish to call them, were introduced in 1999 or so - I don't actually recall now. The main claim to them was that they contained Kevlar. All still made by Gates and marked as made in the UK, but not available outside of Ducati. Some were a bit more expensive, the Testastretta belts a lot so.
Whether or not all the red letter belts actually contain Kevlar, I have no idea. If you can find someone at Gates who does know, pass it on.
As to the two year replacement interval thing: Firstly, I have no interest in arguing this in the slightest. Absolutely none. Believe it. Don't believe it. I don't give a rat's arse. But every official Ducati workshop manual from 2000 until the MTS1200 has had the two year replacement regardless of km specified. At the bottom of the scheduled maintenance chart or on the next page, it will have the note corresponding to the (*) or (1) after the Timing belt line saying "Replace every two years, in any case." With the MTS1200 and Diavel it became 5 years. As I'm not part of the dealer network, I didn't get the official explanation as to why.
As to how often I change my belts: I have only had one belt drive bike in use long enough to require belt changes, but then again it's also on its third engine in its time with me and there's been a bit of idle time. I think only the 750 engine has had belts in it long enough to need them to be replaced, and I only did that when I realised (after noticing the dates on dyno runs) they were over 5 years old. I'd guess the belts in the 851 are getting on for 15 years old now, but it hasn't run in 12 years so that's no big deal. Everything else has been moved on before time. But I'm a tight arse too, so any belts in my bikes will be in there for as long as I can withstand the niggling paranoia of impending doom.
I've not used any of the Dayco belts. As the Australian distributor for California Cycleworks products, I use the Exactfit belts as the aftermarket option.
Saturday, February 11, 2017
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.