The other day when I was riding my bike it started making this unsusual echoy ringing sound. Similar to the sound your chain makes when it is not oiled. It was only noticebale when i revved the bike. This started about halfway through the ride. I have a leaky countershaft seal behind my front sprocket and a bit of oil leaked out during the ride. I thought the sound may be due to the lack of gearbox oil however I loosened the check bolt and oil came out so there was enough. I went on a couple of rides later in the day and at first the sound went away however about 5 minutes into the ride it came back again. Not sure if this is related but it is very hard to start the bike in gear with the clutch in. It feals as though the clutch isnt engaging properly. Also it sometimes feals like the clutch is slipping when I'm riding. Any help or advice would be much aprecciated.