What year is that FZ1? I ask because if its a 2007 or older it could be the epoxy resin that hold the magnets on the inside of the alternator coming loose. If it is that then you need to stop riding the bike immediately! http://www.youtube.com/watch?v=KBTm2b7f6Gc
This might sound a bit daft but I had a similar problem with my wifes car engine last year , That turned out to be a leaf that had been sucked into the air box, dried out and was vibrating against the air filter
It will run without it being plugged in, but if you remove the assembly you wont be able to start it as the starter clutch is all part of the rotor assembly on the back. You can tell quite easily if the bearings are shot simply, by stripping the rotor and spinning by hand. What need to be checked is wear on parts of the replacement rotor to ensure they're correct tolerance and the bearings aren't spinning, in their rebates or on the shafts.
From memory, the stub axle is a push fit, gently heat the casing and it should drop out. It's normally the generator shaft bearing that fails in my experience, that the one in engine case. https://www.r1-forum.com/threads/starter-clutch-bearing-install.568473/If the front cover bearing has gone you will be able to feel and hear it.
But as you can see from the pics and videos, theu are both fine? Both operate correctly, no noises or resistance??So I'm baffled as it sounds like it should be the bearings
Quote from: Dudeofrude on 20 October 2020, 01:42:58 pmBut as you can see from the pics and videos, theu are both fine? Both operate correctly, no noises or resistance??So I'm baffled as it sounds like it should be the bearingsAs mentioned earlier these noises can be notoriously difficult to find at times. Have you checked the airbox intake along it's whole length, air filter not torn, throttle body rubbers to head and to the bodies? Failing that, the clutch has a few bearings, oil and water pump drive chain or one of the pumps, or the gear box. If you pull the clutch in does the noise change, on the main stand and in gear let the clutch out (be careful) increase the revs, is it still there better worse, same?
B. Spend the money replacing to 2 seemly fine bearings just for the sake of it to see if that fixes things
Quote from: Dudeofrude on 20 October 2020, 05:44:06 pmB. Spend the money replacing to 2 seemly fine bearings just for the sake of it to see if that fixes things This is a f*** load cheaper than trying to repair/replace and engine if the bearings let go.@Gnasher does Dude have to buy genuine or will these bearings (like most bearings) have a bearing code of them so he can get a set from a reputable bearing supplier?