Not sure if I can be any more vague but I have noticed a noise , normally when freewheeling down drive or manually moving when engine is off but there is a knocking noise come from around the front sprocket area, however, i don't think its the actual front sprocket itself, sounds more like what it feeds in to. The chain sort of clicks and jumps up and down ever so slightly but it does this in time with the click/knocking noise. Difficult to explain. Chain is lubed. Has it up on centre stand earlier and moving the wheel by hand but It also happens when engine is running just not as noticeable because of the engine noise but obviously still there. Appreciate any help - thanks.