i bought my 81 gs 550 for 400 bucs and put another 160 in it for a custom choke and getting the carbs cleaned and wanted to have the rubbing/grinding noise looked at but they said they didnt notice anything. i can hear it and i know everyone else can also as i drive by. it sounds like the bearings have a flat spot or the brakes are warped ´cuz its a hit and mis and increases with speed. its quite embarasing and i am afriad that if its a wheel bearing that it may sieze up or cause more serious damage. please if any one has known of a cure than please help me.