"Larry Gagnon" wrote:

I have Shimano 105 flight deck shift levers, mated to Shimano 105 rear
derailleur on a touring bike. Recently, when pushing the right hand (rear
derailleur) shift lever to the left in order to shift from a smaller to a
larger rear sprocket it often requires two pushes - the first push is very
loose and then it finally catches and increases tension.

It seems to me this might be due to a gummed up or sticky rear derailleur
cable but I'm not sure. Has anyone else experienced this and know a fix?

That doesn't sound good. The more common symptom is sluggishness when
shifting to a smaller cog. That can sometimes be helped with a WD-40 flush.

In your case, it sounds more like something isn't "catching" in the lever. I
was on a ride once when someone's lever just stopped shifting at all when he
moved the lever. We managed to get him home by using the der limit screw to
get him in a middle gear.

If you're bike/lever is less than 2-years old, you're covered under
warranty.

Art Harris