I just finished cleaning and relubing an 83 Trek 520. The Suntour dt shifters still do not work smoothly and the friction tension is basicly either too tight or too loose. There does not seem to be a middle ground. On the far inside of the lever there is a thin metal 'washer' that still has some rust on both sides of the washer. It is so thin and delicate I was afraid to do much to it. Is this the reason for the poor shifter feel?

BTW...I was pleasantly surprised with the good ride of this bike. It was not slow and sluggish as I had expected. Really a nice ride and I may keep it instead of selling it as intended.