I'm out in the desert and got back from a ride yesterday and when I let off the throttle and the "engine braking" is on it makes a high pitched whining noise. Sounds like its coming from the clutch trans area. I'm not gonna tear into out here but thought I would ask what it might be. Is this a common thing? Belt? I've done the sheave and greaseless weights. Everything on the outside looks fine nothing obvious. Thanks for any suggestions.