I just finished a top end rebuild on my 04 - 250, Everything seems to be running great, no problems with power, idling, anything. However I seem to be getting some kind of hissing or airleak noise. The noise mostly occurs on the deceleration of the motor, it may occur also on acceleration however I cannot hear it over the exhaust. To me it sounds like the rad cap was leaking, but there was nothing there and I dont seem to be losing fluid. I alos put a new EBC clutch in the bike, the clutch needs to be adjusted as it is a bit grabby, could this be making the noise? I also installed new Boysen reeds are they prone to any problems? Any ideas of what to check and how to check would be appreciated.