Originally Posted by
Trinidor
Had a hunch, maybe the lever bolt was too tight. Seems I was right. Loosened the bolt and all seems to be well, back and forth between SIS and friction seems to be working. Sorry for the bother. Maybe this simple solution can make somebody else's day! Cheers
Good catch on that these two function late 80's early 90's light action Shimmano shifters can be a bit touchy if any of the adjustments are off several of the bikes I have had with them required light tuning about every couple hundred miles.