i replaced the clutch in my 2000 rm125 and it ran great the first few times out, now when i start the bike up after its been sitting for a while its a really rough shift into first, the bike will jump and then stall. So to get around this i would rev up the engine then shift and once i got past this i could shift into first fine all day long. any ideas? i am going to change the oil in it before i go riding again.