I had to be recovered home today halfway through a ride out. The bike felt more vibey than normal and strange noises were coming from the engine. No loss of power but no way I dared to ride it any further Striped it down and found distroyed alternator bearing. Has anyone else had this issue I am kind of worried why this has happened. Googling it does not bring anything up
I have a feeling the culprit is the left main bearing. There is a little bit of vertical movement and a definate small knock when I pull the crack upwards. Horizontally there is no movement though.
What causes a main bearing to fail in such a way? It just seemed to come from nowhere with no warning , I have done 3 trackdays on this one and I change the oil every 3k miles regardless. The oil that I dropped last night is about 1500 miles old and was still quite golden.
Has the bike ever been on it's side, running?? That's pretty much a killer for the mains. There could be all sorts of causes unfortunately......could be simply component wear/failure, if the alternator has been off/checked and the shim has slipped down on reassembly then the whole gen'y assembly goes out of balance. I'm rebuilding a ST that looks to have been shimmed up too tight on the crank preload.....and that's shot the mains. Doubt the trackdays have been a factor. There's so many factors it's hard to pin down without the history and actually inspecting things as they come apart. Could simply be the bearing in the cover was a bad 'un and has failed????
I have had it about 18 months and done about 4k miles with it. Its been faultless untill yesterday with no strange sounds or hint of what was due to come. I think I'll just have to put it down to one of those things.
