I had a strange bit of damage to my belt back in 2016 - see below: https://www.ducatiforum.co.uk/threads/1098r-cam-belt-is-this-normal.43307/
the way people video everything now, it's possible it's already out there, but if not - it would be interesting to see the gradual meltdown of a timing belt. When you come across the shredded remainder of the belt that looks like a bundle of tangled hair, it's taken "a while" to create this, it doesn't happen in one revolution of an engine. The belt can takes a "hit" and is fractured as a result but still might be ok for many miles before the delamination all gets in the way and the structure decides to call it a day.
I agree on this, if that little "cylinder" is only plastic it should be properly bashed up...or it hasn't had anything to do with the belt failure.
that is a good point but depending how compliant it is/what it's made of, it wouldn't necessarily have been affected at all, it only had to get sucked in for one rotation of a sprocket to create a fracture. it can't be ruled out that this wasn't even the culprit. are there any tell-tale marks on close examination @bigjimmyb ?
I guess I should be saying I 'think' it might be the culprit, seeing as it is a loose foreign body in the belt case - I can;t see anything else that would have caused it and am told the belts don't just snap of their own accord. Something has got behind the belt on the pulley and torn it down the middle (along the length of the belt), which then weakened it, leading to its' eventual failure. There are no significant marks on the foreign body. It is hard plastic, with very little flex. As stated above, it may only have had to be in the pulley for a very short amount of time to have caused the issue.
Quick update.... I took the bike to Glenn at Moto V and he put a borescope in and the valve is in there in an odd place (not the right place!) and that and the piston are covered in dings - it's cooked. So am on the lookout for a reasonably priced used head (complete), barrel and piston. There's a bike breaking on eBay so I've messaged the seller for those bits, but if anyone has other suggestions, fire away! Glenn is busy til Nov so time to scavenge some parts. I may also be working by then so can pay for it. Thanks BJB And special thank to @RickyX for the spare belts and @NineNineSix for the kind offer of the 'scope.
Speaking of piston crowns covered in dings, I just posted this pic of one of mine on the Alfa Romeo thread…