Out of interest has anyone known of or suffered from a belt or belts breaking ? I know we constantly change them every two years or so but what happens when we don't
There is quite a bit about this on another thread about servicing and there seems to be mixed opinions with some changing them religeously every 2 years right through to one poster saying up to 8 years. I do mine every 4 years and have had no problems. That said I`m sure there will be the odd disaster story.
Wot he said...................... Personally I am 100 % happy to go to 3 year intervals particularly if the bike is used . The worst thing is a bike that is laid up as the belts get stressed unevenly.
Belts would only break if tensioned too tight/loose IMHO? Too loose is the usual offender, the pulleys then chew them up... Car belts break (mainly due to being well out of their service life...) but we still keep buying cars lol
I had the horizontal cylinder belt break on my 888 SP2 when I had it delivered home...it was due to go into Moto Cinelli ( one of the importers at the time ) to have them done as well as a full top to tail, front to back service........I had bought it from a dealer in Italy and had it shipped home, and instead of taking it up on the trailer, it was a nice day so thought I'd ride it to Northampton. I got 7 miles......4 new valves, seats, guides, a piston, a barrel, later, it was repaired. If you want to risk that then on your head be it........thats my tuppence worth....
A lot of sense here, we do carry on buying and abusing the service intervals, i think the belt question has to be in your own hands, personally, i would be happy to let it go for 4 years, maybe even five, then i don't get out on the bike that often, the motor gets turned regular, and most important, i dont run any belt covers. so easy to check for tension and damage, but thats my opinion, and i am sticking to it. i think if i did serious miles i would rethink this.
I got a Pantah in May 1980, when they first came out. At the time belt driven Ducatis had only just come in, and nobody had any idea how to set the tension. Mine seemed a bit slack to me, so I tightened them slightly. Turned out they were now too tight, and snapped on a ride to Norwich. We learned that they should be slightly slack with engine cold. Nowadays, there are several sophisticated methods for setting belt tension, not just by "feel".
Lost the rear belt on my 851 years ago, got away with 4 bent valves and considered myself very lucky.
Stretch the interval and prepare to stretch your wallet. Horizontal belt on 916 Bip (18,000 miles) let go at 140mph - not pretty.
I'm of the opinion that two years on the Pantah is probably a bit over cautious, but when the belts are so incredibly cheap and easy (got my belts from nog, and I fit them myself) I see no reason to stretch the interval.
I *almost* had one go - I bought a race engine to fit in my DD bike (going from 600 to 620) and the bike it was previously in had been in the gravel trap a few races before the end of the season. When we were fitting the engine, it got a full service and on taking the belt covers off there was a small piece of flint which had got trapped inside and had worn the side/edge of the belt. It was split roughly 3/4 of the way across in one spot! In this case it was obviously wear which would have cause the belt to snap, but preventative maintenance that spotted it. I'm now paranoid so check my belts every oil service (normally every year) just to make sure they're still in one piece. You don't have to take them off, just take the belt covers off and check they look good.
I've only experienced one failure and was lucky it was very close to TDC firing on the front cylinder of a two valve. This was caused by the 'tongue' part of the flexible plastic cam sprocket backplate being incorrectly fitted. It's worth mentioning here that (not only due to the potentially higher repair cost) the 4 valvers are more at risk here due to smaller cam sprocket wrap and the sustained higher revs. On 2 and 4 valvers the tensioner and idler bearings often get overlooked and their full or partial seizing can be the sole cause for belt failure, it's always worth examining the back face of the belt for unusual signs of abrading and wear while you're routinely checking the toothed face and the tension.
That's a bit expensive! That's more like it. From memory, the belts for the 998 are the same as my big Monster. They're certainly not anything like that much. You're nearly into RS territory at £140.
The determining factor here seems to be usage. If a bike is used regularly and not left standing for more than a week or two at a time, the contant usage and heat cycling seems to make the belts last longer. Tensioning every year, according to the new Hz method (110 for new belts, 90-100 for re-tensioning old belts), seems to make them last long beyond the 12k miles or two year mark. A lot of people who home change the belts and are adept at setting tension correctly, seem to be able to make them safely last, but it appears with regular inspection. That said, this is only if they display no fraying, degrading or damage whatsoever. Any laying up on the order of months seems to make them deteriorate to a large degree that can mean all bets are off. A
Sounds like a reasonable answer, to yet there has been no mention as to the age of the belt? to throw a low ball in, "what if" the brand new belts you buy have been on the shelf for ages, years maybe in the case of a pantah. how would you know? they are rubber, just like tyres!
No, that's a fair point. However, belts under tension are very different from belts at a rest on shelf. The job a belt does on a bike, is usually a fair bit more stressful than that done in a car, due to the routing, pulley size and placement and the resulting tension required, hence the shorter intervals. My Mistubish Carisma gets 60k miles on belt! Of course you could get a combination of a long shelf life belt and bad tensioning and therefore a bad experience but, again, inspection and correct tensioning should be the best guide. I examined the belts that came from my ST4s after doing 14k miles in two years and they looked absolutely perfect. Not bag fresh, but no visible signs of either wear or damage, but thay had been retensioned mid life by an expert too. A
