Well at the end of day 3 in Andalucia, Spain this happened. On first inspection, it looks like one of the collets that sits on top of the valves has somehow worked loose and eventually got picked up by the cam and ejected through the head cover. Bikes still on it’s way back from Spain so couldn’t be bothered stripping it down and shipping it in bits. I only went as far as taking the cover off and removing the cams. Fingers crossed it’s just a top end but I have no experience with this before so completely in the dark until next week. Has anyone had this happen before? I think I was on my best lap of the weekend when this happened.
What sort of age and mileage is the bike? And did it do it under braking on downshifting or on the power? Hate to say it but from my limited knowledge there is a good chance it’s dropped the valve, unless there are two collets and the lower rocker has held it up
its a TriOptions bike, 2014 with 5k on. It happend on the entry to the last corner. Downshift from 4th to 3rd. Bike cut out straight away and I managed to coast it round to pit exit. Bike is back this weekend but I’m away so I’ll get a better look at it next week. Just thought I’d get an early feel for what I’m looking at. Would it have a knock on effect with the front cylinder and or the bottom end aswell? It seems to still go through all the gears fine. Thanks for the info.
Sounds like you have done a Chris Walker tbh... Regards damage to the other cylinder, impossible to say, if something has been in contact with the piston and stopped it while the other piston is on a firing stroke it could well have bent a conrod etc, you just won't know until you get it apart tbh, but absolutely don't even turn it over until you strip it.
